Wed, 14 Mar 2012 20:06:48 -0700
7123170: JCK vm/jvmti/ResourceExhausted/resexh001/resexh00101/ tests fails since 7u4 b02
Summary: The JVMTI ResourceExhausted events must be generated in all places where OOME is thrown
Reviewed-by: acorn, coleenp, dcubed, dholmes, dsamersoff, jwilhelm, tonyp
Contributed-by: serguei.spitsyn@oracle.com
1 <?xml version="1.0" encoding="ISO-8859-1"?>
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25 -->
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356 ]>
358 <specification label="JVM(TM) Tool Interface"
359 majorversion="1"
360 minorversion="2"
361 microversion="1">
362 <title subtitle="Version">
363 <tm>JVM</tm> Tool Interface
364 </title>
366 <intro id="whatIs" label="What is the JVM Tool Interface?">
367 The <tm>JVM</tm> Tool Interface (<jvmti/>)
368 is a programming interface used by development and monitoring tools.
369 It provides both a way to inspect the state and
370 to control the execution of applications running in the
371 <tm>Java</tm> virtual machine (VM).
372 <p/>
373 <jvmti/> is intended to provide a VM interface for the full breadth of tools
374 that need access to VM state, including but not limited to: profiling,
375 debugging, monitoring, thread analysis, and coverage analysis tools.
376 <p/>
377 <jvmti/> may not be available in all implementations of the <tm>Java</tm> virtual
378 machine.
379 <p/>
380 <jvmti/> is a two-way interface.
381 A client of <jvmti/>, hereafter called an <i>agent</i>,
382 can be notified of
383 interesting occurrences through <internallink id="EventSection">events</internallink>.
384 <jvmti/>
385 can query and control the application through many
386 <internallink id="FunctionSection">functions</internallink>,
387 either in response to events or
388 independent of them.
389 <p/>
390 Agents run in the same process with and communicate directly with
391 the virtual machine executing
392 the application being examined. This communication is
393 through a native interface (<jvmti/>). The native in-process interface allows
394 maximal control with minimal intrusion on the part of a tool.
395 Typically, agents are relatively compact. They can be controlled
396 by a separate process which implements the bulk of a tool's
397 function without interfering with the target application's normal execution.
398 </intro>
400 <intro id="architecture" label="Architecture">
401 Tools can be written directly to <jvmti/> or indirectly
402 through higher level interfaces.
403 The Java Platform Debugger Architecture includes <jvmti/>, but also
404 contains higher-level, out-of-process debugger interfaces. The higher-level
405 interfaces are more appropriate than <jvmti/> for many tools.
406 For more information on the Java Platform Debugger Architecture,
407 see the
408 <externallink id="http://java.sun.com/products/jpda/">Java
409 Platform Debugger Architecture website</externallink>.
410 </intro>
412 <intro id="writingAgents" label="Writing Agents">
413 Agents can be written in any native language that supports C
414 language calling conventions and C or C++
415 definitions.
416 <p/>
417 The function, event, data type, and constant definitions needed for
418 using <jvmti/> are defined in the include file <code>jvmti.h</code>.
419 To use these definitions add the <tm>J2SE</tm> include directory
420 to your include path and add
421 <example>
422 #include <jvmti.h>
423 </example>
424 to your source code.
425 </intro>
427 <intro id="deployingAgents" label="Deploying Agents">
428 An agent is deployed in a platform specific manner but is typically the
429 platform equivalent of a dynamic library. On the <tm>Windows</tm> operating
430 system, for example, an agent library is a "Dynamic Linked Library" (DLL).
431 On the <tm>Solaris</tm> Operating Environment, an agent library is a shared
432 object (<code>.so</code> file).
433 <p/>
434 An agent may be started at VM startup by specifying the agent library
435 name using a <internallink id="starting">command line option</internallink>.
436 Some implementations may support a mechanism to <internallink id="onattach">
437 start agents</internallink> in the live <functionlink id="GetPhase">phase</functionlink>.
438 The details of how this is initiated are implementation specific.
439 </intro>
441 <intro id="starting" label="Agent Command Line Options">
442 The term "command-line option" is used below to
443 mean options supplied in the <code>JavaVMInitArgs</code> argument
444 to the <code>JNI_CreateJavaVM</code> function of the JNI
445 Invocation API.
446 <p/>
447 One of the two following
448 command-line options is used on VM startup to
449 properly load and run agents.
450 These arguments identify the library containing
451 the agent as well as an options
452 string to be passed in at startup.
453 <dl>
454 <dt><code>-agentlib:</code><i><agent-lib-name></i><code>=</code><i><options></i></dt>
455 <dd>
456 The name following <code>-agentlib:</code> is the name of the
457 library to load. Lookup of the library, both its full name and location,
458 proceeds in a platform-specific manner.
459 Typically, the <i><agent-lib-name></i> is expanded to an
460 operating system specific file name.
461 The <i><options></i> will be passed to the agent on start-up.
462 For example, if the option
463 <code>-agentlib:foo=opt1,opt2</code> is specified, the VM will attempt to
464 load the shared library <code>foo.dll</code> from the system <code>PATH</code>
465 under <tm>Windows</tm> or <code>libfoo.so</code> from the
466 <code>LD_LIBRARY_PATH</code> under the <tm>Solaris</tm> operating environment.
467 </dd>
468 <dt><code>-agentpath:</code><i><path-to-agent></i><code>=</code><i><options></i></dt>
469 <dd>
470 The path following <code>-agentpath:</code> is the absolute path from which
471 to load the library.
472 No library name expansion will occur.
473 The <i><options></i> will be passed to the agent on start-up.
474 For example, if the option
475 <code>-agentpath:c:\myLibs\foo.dll=opt1,opt2</code> is specified, the VM will attempt to
476 load the shared library <code>c:\myLibs\foo.dll</code>.
477 </dd>
478 </dl>
479 The start-up routine <internallink id="onload"><code>Agent_OnLoad</code></internallink>
480 in the library will be invoked.
481 <p/>
482 Libraries loaded with <code>-agentlib:</code> or <code>-agentpath:</code>
483 will be searched for JNI native method implementations to facilitate the
484 use of Java programming language code in tools, as is needed for
485 <internallink id="bci">bytecode instrumentation</internallink>.
486 <p/>
487 The agent libraries will be searched after all other libraries have been
488 searched (agents wishing to override or intercept the native method
489 implementations of non-agent methods can use the
490 <eventlink id="NativeMethodBind">NativeMethodBind event</eventlink>).
491 <p/>
492 These switches do the above and nothing more - they do not change the
493 state of the VM or <jvmti/>. No command line options are needed
494 to enable <jvmti/>
495 or aspects of <jvmti/>, this is handled programmatically
496 by the use of
497 <internallink id="capability">capabilities</internallink>.
498 </intro>
500 <intro id="startup" label="Agent Start-Up">
501 The VM starts each agent by invoking a start-up function.
502 If the agent is started in the <code>OnLoad</code>
503 <functionlink id="GetPhase">phase</functionlink> the function
504 <internallink id="onload"><code>Agent_OnLoad</code></internallink>
505 will be invoked.
506 If the agent is started in the live
507 <functionlink id="GetPhase">phase</functionlink> the function
508 <internallink id="onattach"><code>Agent_OnAttach</code></internallink>
509 will be invoked.
510 Exactly one call to a start-up function is made per agent.
511 </intro>
513 <intro id="onload" label="Agent Start-Up (OnLoad phase)">
514 If an agent is started during the <code>OnLoad</code> phase then its
515 agent library must export a start-up function with the following prototype:
516 <example>
517 JNIEXPORT jint JNICALL
518 Agent_OnLoad(JavaVM *vm, char *options, void *reserved)</example>
519 The VM will start the agent by calling this function.
520 It will be called early enough in VM initialization that:
521 <ul>
522 <li><functionlink id="SetSystemProperty">system properties</functionlink>
523 may be set before they have been used in the start-up of the VM</li>
524 <li>the full set of
525 <internallink id="capability">capabilities</internallink>
526 is still available (note that capabilities that configure the VM
527 may only be available at this time--see the
528 <internallink id="capability">Capability function section</internallink>)</li>
529 <li>no bytecodes have executed</li>
530 <li>no classes have been loaded</li>
531 <li>no objects have been created</li>
532 </ul>
533 <p/>
534 The VM will call the <code>Agent_OnLoad</code> function with
535 <i><options></i> as the second argument -
536 that is, using the command-line option examples,
537 <code>"opt1,opt2"</code> will be passed to the <code>char *options</code>
538 argument of <code>Agent_OnLoad</code>.
539 The <code>options</code> argument is encoded as a
540 <internallink id="mUTF">modified UTF-8</internallink> string.
541 If <i>=<options></i> is not specified,
542 a zero length string is passed to <code>options</code>.
543 The lifespan of the <code>options</code> string is the <code>Agent_OnLoad</code>
544 call. If needed beyond this time the string or parts of the string must
545 be copied.
546 The period between when <code>Agent_OnLoad</code> is called and when it
547 returns is called the <i>OnLoad phase</i>.
548 Since the VM is not initialized during the OnLoad
549 <functionlink id="GetPhase">phase</functionlink>,
550 the set of allowed operations
551 inside <code>Agent_OnLoad</code> is restricted (see the function descriptions for the
552 functionality available at this time).
553 The agent can safely process the options and set
554 event callbacks with <functionlink id="SetEventCallbacks"></functionlink>. Once
555 the VM initialization event is received
556 (that is, the <eventlink id="VMInit">VMInit</eventlink>
557 callback is invoked), the agent
558 can complete its initialization.
559 <rationale>
560 Early startup is required so that agents can set the desired capabilities,
561 many of which must be set before the VM is initialized.
562 In JVMDI, the -Xdebug command-line option provided
563 very coarse-grain control of capabilities.
564 JVMPI implementations use various tricks to provide a single "JVMPI on" switch.
565 No reasonable command-line
566 option could provide the fine-grain of control required to balance needed capabilities vs
567 performance impact.
568 Early startup is also needed so that agents can control the execution
569 environment - modifying the file system and system properties to install
570 their functionality.
571 </rationale>
572 <p/>
573 The return value from <code>Agent_OnLoad</code> is used to indicate an error.
574 Any value other than zero indicates an error and causes termination of the VM.
575 </intro>
577 <intro id="onattach" label="Agent Start-Up (Live phase)">
578 A VM may support a mechanism that allows agents to be started in the VM during the live
579 <functionlink id="GetPhase">phase</functionlink>. The details of how this is supported,
580 are implementation specific. For example, a tool may use some platform specific mechanism,
581 or implementation specific API, to attach to the running VM, and request it start a given
582 agent.
583 <p/>
584 If an agent is started during the live phase then its agent library
585 must export a start-up function
586 with the following prototype:
587 <example>
588 JNIEXPORT jint JNICALL
589 Agent_OnAttach(JavaVM* vm, char *options, void *reserved)</example>
590 <p/>
591 The VM will start the agent by calling this function.
592 It will be called in the context of a thread
593 that is attached to the VM. The first argument <i><vm></i> is the Java VM.
594 The <i><options></i> argument is the startup options provided to the agent.
595 <i><options></i> is encoded as a <internallink id="mUTF">modified UTF-8
596 </internallink> string.
597 If startup options were not provided, a zero length string is passed to
598 <code>options</code>. The lifespan of the <code>options</code> string is the
599 <code>Agent_OnAttach</code> call. If needed beyond this time the string or parts of
600 the string must be copied.
601 <p/>
602 Note that some <internallink id="capability">capabilities</internallink>
603 may not be available in the live phase.
604 <p/>
605 The <code>Agent_OnAttach</code> function initializes the agent and returns a value
606 to the VM to indicate if an error occurred. Any value other than zero indicates an error.
607 An error does not cause the VM to terminate. Instead the VM ignores the error, or takes
608 some implementation specific action -- for example it might print an error to standard error,
609 or record the error in a system log.
610 </intro>
612 <intro id="onunload" label="Agent Shutdown">
613 The library may optionally export a
614 shutdown function with the following prototype:
615 <example>
616 JNIEXPORT void JNICALL
617 Agent_OnUnload(JavaVM *vm)</example>
618 This function will be called by the VM when the library is about to be unloaded.
619 The library will be unloaded and this function will be called if some platform specific
620 mechanism causes the unload (an unload mechanism is not specified in this document)
621 or the library is (in effect) unloaded by the termination of the VM whether through
622 normal termination or VM failure, including start-up failure.
623 Uncontrolled shutdown is, of couse, an exception to this rule.
624 Note the distinction between this function and the
625 <eventlink id="VMDeath">VM Death event</eventlink>: for the VM Death event
626 to be sent, the VM must have run at least to the point of initialization and a valid
627 <jvmti/> environment must exist which has set a callback for VMDeath
628 and enabled the event
629 None of these are required for <code>Agent_OnUnload</code> and this function
630 is also called if the library is unloaded for other reasons.
631 In the case that a VM Death event is sent, it will be sent before this
632 function is called (assuming this function is called due to VM termination).
633 This function can be used to clean-up resources allocated by the agent.
634 </intro>
636 <intro id="tooloptions" label="JAVA_TOOL_OPTIONS">
637 Since the command-line cannot always be accessed or modified, for example in embedded VMs
638 or simply VMs launched deep within scripts, a <code>JAVA_TOOL_OPTIONS</code> variable is
639 provided so that agents may be launched in these cases.
640 <p/>
641 Platforms which support environment variables or other named strings, may support the
642 <code>JAVA_TOOL_OPTIONS</code> variable. This variable will be broken into options at white-space
643 boundaries. White-space characters include space, tab, carriage-return, new-line,
644 vertical-tab, and form-feed. Sequences of white-space characters are considered
645 equivalent to a single white-space character. No white-space is included in the options
646 unless quoted. Quoting is as follows:
647 <ul>
648 <li>All characters enclosed between a pair of single quote marks (''), except a single
649 quote, are quoted.</li>
650 <li>Double quote characters have no special meaning inside a pair of single quote marks.</li>
651 <li>All characters enclosed between a pair of double quote marks (""), except a double
652 quote, are quoted.</li>
653 <li>Single quote characters have no special meaning inside a pair of double quote marks.</li>
654 <li>A quoted part can start or end anywhere in the variable.</li>
655 <li>White-space characters have no special meaning when quoted -- they are included in
656 the option like any other character and do not mark white-space boundaries.</li>
657 <li>The pair of quote marks is not included in the option.</li>
658 </ul>
659 <code>JNI_CreateJavaVM</code> (in the JNI Invocation API) will prepend these options to the options supplied
660 in its <code>JavaVMInitArgs</code> argument. Platforms may disable this feature in cases where security is
661 a concern; for example, the Reference Implementation disables this feature on Unix systems when
662 the effective user or group ID differs from the real ID.
663 This feature is intended to support the initialization of tools -- specifically including the
664 launching of native or Java programming language agents. Multiple tools may wish to use this
665 feature, so the variable should not be overwritten, instead, options should be appended to
666 the variable. Note that since the variable is processed at the time of the JNI Invocation
667 API create VM call, options processed by a launcher (e.g., VM selection options) will not be handled.
668 </intro>
670 <intro id="environments" label="Environments">
671 The <jvmti/> specification supports the use of multiple simultaneous
672 <jvmti/> agents.
673 Each agent has its own <jvmti/> environment.
674 That is, the <jvmti/> state is
675 separate for each agent - changes to one environment do not affect the
676 others. The state of a <jvmti/>
677 environment includes:
678 <ul>
679 <li><functionlink id="SetEventCallbacks">the event callbacks</functionlink></li>
680 <li><functionlink id="SetEventNotificationMode">the set of events which are enabled</functionlink></li>
681 <li><internallink id="capability">the capabilities</internallink></li>
682 <li><internallink id="memory">the memory allocation/deallocation hooks</internallink></li>
683 </ul>
684 Although their <jvmti/> state
685 is separate, agents inspect and modify the shared state
686 of the VM, they also share the native environment in which they execute.
687 As such, an agent can perturb the results of other agents or cause them
688 to fail. It is the responsibility of the agent writer to specify the level
689 of compatibility with other agents. <jvmti/> implementations are not capable
690 of preventing destructive interactions between agents. Techniques to reduce
691 the likelihood of these occurrences are beyond the scope of this document.
692 <p/>
693 An agent creates a <jvmti/> environment
694 by passing a <jvmti/> version
695 as the interface ID to the JNI Invocation API function
696 <externallink id="http://java.sun.com/javase/6/docs/technotes/guides/jni/spec/invocation.html#GetEnv"><code>GetEnv</code></externallink>.
697 See <internallink id="jvmtiEnvAccess">Accessing <jvmti/> Functions</internallink>
698 for more details on the creation and use of
699 <jvmti/> environments.
700 Typically, <jvmti/> environments are created by calling <code>GetEnv</code> from
701 <internallink id="onload"><code>Agent_OnLoad</code></internallink>.
702 </intro>
704 <intro id="bci" label="Bytecode Instrumentation">
705 This interface does not include some events that one might expect in an interface with
706 profiling support. Some examples include object allocation events and full speed
707 method enter and exit events. The interface instead provides support for
708 <i>bytecode instrumentation</i>, the ability to alter the Java virtual machine
709 bytecode instructions which comprise the target program. Typically, these alterations
710 are to add "events" to the code of a method - for example, to add, at the beginning of a method,
711 a call to <code>MyProfiler.methodEntered()</code>.
712 Since the changes are purely additive, they do not modify application
713 state or behavior.
714 Because the inserted agent code is standard bytecodes, the VM can run at full speed,
715 optimizing not only the target program but also the instrumentation. If the
716 instrumentation does not involve switching from bytecode execution, no expensive
717 state transitions are needed. The result is high performance events.
718 This approach also provides complete control to the agent: instrumentation can be
719 restricted to "interesting" portions of the code (e.g., the end user's code) and
720 can be conditional. Instrumentation can run entirely in Java programming language
721 code or can call into the native agent. Instrumentation can simply maintain
722 counters or can statistically sample events.
723 <p/>
724 Instrumentation can be inserted in one of three ways:
725 <ul>
726 <li>
727 Static Instrumentation: The class file is instrumented before it
728 is loaded into the VM - for example, by creating a duplicate directory of
729 <code>*.class</code> files which have been modified to add the instrumentation.
730 This method is extremely awkward and, in general, an agent cannot know
731 the origin of the class files which will be loaded.
732 </li>
733 <li>
734 Load-Time Instrumentation: When a class file is loaded by the VM, the raw
735 bytes of the class file are sent for instrumentation to the agent.
736 The <eventlink id="ClassFileLoadHook"/>
737 event, triggered by the class load,
738 provides this functionality. This mechanism provides efficient
739 and complete access to one-time instrumentation.
740 </li>
741 <li>
742 Dynamic Instrumentation: A class which is already loaded (and possibly
743 even running) is modified. This optional feature is provided by the
744 <eventlink id="ClassFileLoadHook"/> event, triggered by calling the
745 <functionlink id="RetransformClasses"/> function.
746 Classes can be modified multiple times and can be returned to their
747 original state.
748 The mechanism allows instrumentation which changes during the
749 course of execution.
750 </li>
751 </ul>
752 <p/>
753 The class modification functionality provided in this interface
754 is intended to provide a mechanism for instrumentation
755 (the <eventlink id="ClassFileLoadHook"/> event
756 and the <functionlink id="RetransformClasses"/> function)
757 and, during development, for fix-and-continue debugging
758 (the <functionlink id="RedefineClasses"/> function).
759 <p/>
760 Care must be taken to avoid perturbing dependencies, especially when
761 instrumenting core classes. For example, an approach to getting notification
762 of every object allocation is to instrument the constructor on
763 <code>Object</code>. Assuming that the constructor is initially
764 empty, the constructor could be changed to:
765 <example>
766 public Object() {
767 MyProfiler.allocationTracker(this);
768 }
769 </example>
770 However, if this change was made using the
771 <eventlink id="ClassFileLoadHook"/>
772 event then this might impact a typical VM as follows:
773 the first created object will call the constructor causing a class load of
774 <code>MyProfiler</code>; which will then cause
775 object creation, and since <code>MyProfiler</code> isn't loaded yet,
776 infinite recursion; resulting in a stack overflow. A refinement of this
777 would be to delay invoking the tracking method until a safe time. For
778 example, <code>trackAllocations</code> could be set in the
779 handler for the <code>VMInit</code> event.
780 <example>
781 static boolean trackAllocations = false;
783 public Object() {
784 if (trackAllocations) {
785 MyProfiler.allocationTracker(this);
786 }
787 }
788 </example>
789 <p/>
790 The <functionlink id="SetNativeMethodPrefix"/> allows native methods
791 to be instrumented by the use of wrapper methods.
792 </intro>
794 <intro id="mUTF" label="Modified UTF-8 String Encoding">
795 <jvmti/> uses modified UTF-8 to encode character strings.
796 This is the same encoding used by JNI.
797 Modified UTF-8 differs
798 from standard UTF-8 in the representation of supplementary characters
799 and of the null character. See the
800 <externallink id="http://java.sun.com/javase/6/docs/technotes/guides/jni/spec/types.html#wp16542">
801 Modified UTF-8 Strings</externallink>
802 section of the JNI specification for details.
803 </intro>
805 <intro id="context" label="Specification Context">
806 Since this interface provides access to the state of applications running in the
807 Java virtual machine;
808 terminology refers to the Java platform and not the native
809 platform (unless stated otherwise). For example:
810 <ul>
811 <li>"thread" means Java programming language thread.</li>
812 <li>"stack frame" means Java virtual machine stack frame.</li>
813 <li>"class" means Java programming language class.</li>
814 <li>"heap" means Java virtual machine heap.</li>
815 <li>"monitor" means Java programming language object monitor.</li>
816 </ul>
817 <p/>
818 Sun, Sun Microsystems, the Sun logo, Java, and JVM
819 are trademarks or registered trademarks of Oracle
820 and/or its affiliates, in the U.S. and other countries.
821 </intro>
824 <functionsection label="Functions">
825 <intro id="jvmtiEnvAccess" label="Accessing Functions">
826 Native code accesses <jvmti/> features
827 by calling <jvmti/> functions.
828 Access to <jvmti/> functions is by use of an interface pointer
829 in the same manner as
830 <externallink id="http://java.sun.com/javase/6/docs/technotes/guides/jni/spec/design.html">Java
831 Native Interface (JNI) functions</externallink> are accessed.
832 The <jvmti/> interface pointer is called the
833 <i>environment pointer</i>.
834 <p/>
835 An environment pointer is a pointer to an environment and has
836 the type <code>jvmtiEnv*</code>.
837 An environment has information about its <jvmti/> connection.
838 The first value in the environment is a pointer to the function table.
839 The function table is an array of pointers to <jvmti/> functions.
840 Every function pointer is at a predefined offset inside the
841 array.
842 <p/>
843 When used from the C language:
844 double indirection is used to access the functions;
845 the environment pointer provides context and is the first
846 parameter of each function call; for example:
847 <example>
848 jvmtiEnv *jvmti;
849 ...
850 jvmtiError err = (*jvmti)->GetLoadedClasses(jvmti, &class_count, &classes);
851 </example>
852 <p/>
853 When used from the C++ language:
854 functions are accessed as member functions of <code>jvmtiEnv</code>;
855 the environment pointer is not passed to the function call; for example:
856 <example>
857 jvmtiEnv *jvmti;
858 ...
859 jvmtiError err = jvmti->GetLoadedClasses(&class_count, &classes);
860 </example>
861 Unless otherwise stated, all examples and declarations in this
862 specification use the C language.
863 <p/>
864 A <jvmti/> environment can be obtained through the JNI Invocation API
865 <code>GetEnv</code> function:
866 <example>
867 jvmtiEnv *jvmti;
868 ...
869 (*jvm)->GetEnv(jvm, &jvmti, JVMTI_VERSION_1_0);
870 </example>
871 Each call to <code>GetEnv</code>
872 creates a new <jvmti/> connection and thus
873 a new <jvmti/> environment.
874 The <code>version</code> argument of <code>GetEnv</code> must be
875 a <jvmti/> version.
876 The returned environment may have a different version than the
877 requested version but the returned environment must be compatible.
878 <code>GetEnv</code> will return <code>JNI_EVERSION</code> if a
879 compatible version is not available, if <jvmti/> is not supported or
880 <jvmti/> is not supported in the current VM configuration.
881 Other interfaces may be added for creating <jvmti/> environments
882 in specific contexts.
883 Each environment has its own state (for example,
884 <functionlink id="SetEventNotificationMode">desired events</functionlink>,
885 <functionlink id="SetEventCallbacks">event handling functions</functionlink>, and
886 <functionlink id="AddCapabilities">capabilities</functionlink>).
887 An environment is released with
888 <functionlink id="DisposeEnvironment"></functionlink>.
889 Thus, unlike JNI which has one environment per thread, <jvmti/> environments work
890 across threads and are created dynamically.
891 </intro>
893 <intro id="functionReturn" label="Function Return Values">
894 <jvmti/> functions always return an
895 <internallink id="ErrorSection">error code</internallink> via the
896 <datalink id="jvmtiError"/> function return value.
897 Some functions can return additional
898 values through pointers provided by the calling function.
899 In some cases, <jvmti/> functions allocate memory that your program must
900 explicitly deallocate. This is indicated in the individual <jvmti/>
901 function descriptions. Empty lists, arrays, sequences, etc are
902 returned as <code>NULL</code>.
903 <p/>
904 In the event that the <jvmti/> function encounters
905 an error (any return value other than <code>JVMTI_ERROR_NONE</code>) the values
906 of memory referenced by argument pointers is undefined, but no memory
907 will have been allocated and no global references will have been allocated.
908 If the error occurs because of invalid input, no action will have occurred.
909 </intro>
911 <intro id="refs" label="Managing JNI Object References">
912 <jvmti/> functions identify objects with JNI references
913 (<datalink id="jobject"/> and <datalink id="jclass"/>)
914 and their derivatives
915 (<datalink id="jthread"/> and <datalink id="jthreadGroup"/>).
916 References passed to
917 <jvmti/> functions can be either global or local, but they must be
918 strong references. All references returned by <jvmti/> functions are
919 local references--these local references are created
920 during the <jvmti/> call.
921 Local references are a resource that must be managed (see the
922 <externallink id="http://java.sun.com/javase/6/docs/guide/jni/spec/functions.html#wp18654">JNI Documentation</externallink>).
923 When threads return from native code all local references
924 are freed. Note that some threads, including typical
925 agent threads, will never return from native code.
926 A thread is ensured the ability to create sixteen local
927 references without the need for any explicit management.
928 For threads executing a limited number of <jvmti/> calls before
929 returning from native code
930 (for example, threads processing events),
931 it may be determined that no explicit management
932 is needed.
933 However, long running agent threads will need explicit
934 local reference management--usually with the JNI functions
935 <code>PushLocalFrame</code> and <code>PopLocalFrame</code>.
936 Conversely, to preserve references beyond the
937 return from native code, they must be converted to global references.
938 These rules do not apply to <datalink id="jmethodID"/> and <datalink id="jfieldID"/>
939 as they are not <datalink id="jobject"/>s.
940 </intro>
942 <intro id="prereqState" label="Prerequisite State for Calling Functions">
943 Unless the function explicitly states that the agent must bring
944 a thread or the VM to a particular state (for example, suspended),
945 the <jvmti/> implementation is responsible for bringing the VM to a
946 safe and consistent state for performing the function.
947 </intro>
949 <intro id="functionsExceptions" label="Exceptions and Functions">
950 <jvmti/> functions never throw exceptions; error conditions are
951 communicated via the
952 <internallink id="functionReturn">function return value</internallink>.
953 Any existing exception state is preserved across a call to a
954 <jvmti/> function.
955 See the
956 <externallink
957 id="http://java.sun.com/javase/6/docs/technotes/guides/jni/spec/design.html#wp770"
958 >Java Exceptions</externallink>
959 section of the JNI specification for information on handling exceptions.
960 </intro>
962 <category id="memory" label="Memory Management">
963 <intro>
964 These functions provide for the allocation and deallocation of
965 memory used by <jvmti/> functionality and can be used to provide
966 working memory for agents.
967 Memory managed by <jvmti/> is not compatible with other memory
968 allocation libraries and mechanisms.
969 </intro>
971 <function id="Allocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="46">
972 <synopsis>Allocate</synopsis>
973 <description>
974 Allocate an area of memory through the <jvmti/> allocator.
975 The allocated
976 memory should be freed with <functionlink id="Deallocate"></functionlink>.
977 </description>
978 <origin>jvmdi</origin>
979 <capabilities>
980 </capabilities>
981 <parameters>
982 <param id="size">
983 <jlong/>
984 <description>
985 The number of bytes to allocate.
986 <rationale>
987 <code>jlong</code> is used for compatibility with JVMDI.
988 </rationale>
989 </description>
990 </param>
991 <param id="mem_ptr">
992 <allocbuf incount="size"><uchar/></allocbuf>
993 <description>
994 On return, a pointer to the beginning of the allocated memory.
995 If <code>size</code> is zero, <code>NULL</code> is returned.
996 </description>
997 </param>
998 </parameters>
999 <errors>
1000 <error id="JVMTI_ERROR_OUT_OF_MEMORY">
1001 Memory request cannot be honored.
1002 </error>
1003 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
1004 <paramlink id="size"></paramlink> is less than zero.
1005 </error>
1006 </errors>
1007 </function>
1009 <function id="Deallocate" jkernel="yes" phase="any" callbacksafe="safe" impl="notrace" num="47">
1010 <synopsis>Deallocate</synopsis>
1011 <description>
1012 Deallocate <code>mem</code> using the <jvmti/> allocator.
1013 This function should
1014 be used to deallocate any memory allocated and returned
1015 by a <jvmti/> function
1016 (including memory allocated with <functionlink id="Allocate"></functionlink>).
1017 All allocated memory must be deallocated
1018 or the memory cannot be reclaimed.
1019 </description>
1020 <origin>jvmdi</origin>
1021 <capabilities>
1022 </capabilities>
1023 <parameters>
1024 <param id="mem">
1025 <outbuf>
1026 <uchar/>
1027 <nullok>the call is ignored</nullok>
1028 </outbuf>
1029 <description>
1030 A pointer to the beginning of the allocated memory.
1031 Please ignore "On return, the elements are set."
1032 <todo>keep it from generating "On return, the elements are set"</todo>
1033 </description>
1034 </param>
1035 </parameters>
1036 <errors>
1037 </errors>
1038 </function>
1039 </category>
1041 <category id="threadCategory" label="Thread">
1042 <intro>
1043 </intro>
1045 <function id="GetThreadState" num="17">
1046 <synopsis>Get Thread State</synopsis>
1047 <description>
1048 Get the state of a thread. The state of the thread is represented by the
1049 answers to the hierarchical set of questions below:
1050 <ul type="circle">
1051 <li><i>Alive?</i>
1052 <ul>
1053 <li>Not alive.
1054 <ul type="circle">
1055 <li><i>Why not alive?</i>
1056 <ul>
1057 <li>New.</li>
1058 <li>Terminated (<datalink
1059 id="JVMTI_THREAD_STATE_TERMINATED"><code>JVMTI_THREAD_STATE_TERMINATED</code></datalink>)</li>
1060 </ul>
1061 </li>
1062 </ul>
1063 </li>
1064 <li>Alive (<datalink
1065 id="JVMTI_THREAD_STATE_ALIVE"><code>JVMTI_THREAD_STATE_ALIVE</code></datalink>)
1066 <ul type="circle">
1067 <li><i>Suspended?</i>
1068 <ul>
1069 <li>Suspended (<datalink
1070 id="JVMTI_THREAD_STATE_SUSPENDED"><code>JVMTI_THREAD_STATE_SUSPENDED</code></datalink>)</li>
1071 <li>Not suspended</li>
1072 </ul>
1073 </li>
1074 <li><i>Interrupted?</i>
1075 <ul>
1076 <li>Interrupted (<datalink
1077 id="JVMTI_THREAD_STATE_INTERRUPTED"><code>JVMTI_THREAD_STATE_INTERRUPTED</code></datalink>)</li>
1078 <li>Not interrupted.</li>
1079 </ul>
1080 </li>
1081 <li><i>In native?</i>
1082 <ul>
1083 <li>In native code (<datalink
1084 id="JVMTI_THREAD_STATE_IN_NATIVE"><code>JVMTI_THREAD_STATE_IN_NATIVE</code></datalink>)</li>
1085 <li>In Java programming language code</li>
1086 </ul>
1087 </li>
1088 <li><i>What alive state?</i>
1089 <ul>
1090 <li>Runnable (<datalink
1091 id="JVMTI_THREAD_STATE_RUNNABLE"><code>JVMTI_THREAD_STATE_RUNNABLE</code></datalink>)</li>
1092 <li>Blocked (<datalink
1093 id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER"><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></datalink>)</li>
1094 <li>Waiting (<datalink
1095 id="JVMTI_THREAD_STATE_WAITING"><code>JVMTI_THREAD_STATE_WAITING</code></datalink>)
1096 <ul type="circle">
1097 <li><i>Timed wait?</i>
1098 <ul>
1099 <li>Indefinite (<datalink
1100 id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY"><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></datalink></li>
1101 <li>Timed (<datalink
1102 id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT"><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></datalink>)</li>
1103 </ul>
1104 </li>
1105 <li><i>Why waiting?</i>
1106 <ul>
1107 <li>Object.wait (<datalink
1108 id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT"><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></datalink>)</li>
1109 <li>LockSupport.park (<datalink
1110 id="JVMTI_THREAD_STATE_PARKED"><code>JVMTI_THREAD_STATE_PARKED</code></datalink>)</li>
1111 <li>Sleeping (<datalink
1112 id="JVMTI_THREAD_STATE_SLEEPING"><code>JVMTI_THREAD_STATE_SLEEPING</code></datalink>)</li>
1113 </ul>
1114 </li>
1115 </ul>
1116 </li>
1117 </ul>
1118 </li>
1119 </ul>
1120 </li>
1121 </ul>
1122 </li>
1123 </ul>
1124 <p/>
1125 The answers are represented by the following bit vector.
1126 <constants id="jvmtiThreadState" label="Thread State Flags" kind="bits">
1127 <constant id="JVMTI_THREAD_STATE_ALIVE" num="0x0001">
1128 Thread is alive. Zero if thread is new (not started) or terminated.
1129 </constant>
1130 <constant id="JVMTI_THREAD_STATE_TERMINATED" num="0x0002">
1131 Thread has completed execution.
1132 </constant>
1133 <constant id="JVMTI_THREAD_STATE_RUNNABLE" num="0x0004">
1134 Thread is runnable.
1135 </constant>
1136 <constant id="JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER" num="0x0400">
1137 Thread is waiting to enter a synchronization block/method or,
1138 after an <code>Object.wait()</code>, waiting to re-enter a
1139 synchronization block/method.
1140 </constant>
1141 <constant id="JVMTI_THREAD_STATE_WAITING" num="0x0080">
1142 Thread is waiting.
1143 </constant>
1144 <constant id="JVMTI_THREAD_STATE_WAITING_INDEFINITELY" num="0x0010">
1145 Thread is waiting without a timeout.
1146 For example, <code>Object.wait()</code>.
1147 </constant>
1148 <constant id="JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT" num="0x0020">
1149 Thread is waiting with a maximum time to wait specified.
1150 For example, <code>Object.wait(long)</code>.
1151 </constant>
1152 <constant id="JVMTI_THREAD_STATE_SLEEPING" num="0x0040">
1153 Thread is sleeping -- <code>Thread.sleep(long)</code>.
1154 </constant>
1155 <constant id="JVMTI_THREAD_STATE_IN_OBJECT_WAIT" num="0x0100">
1156 Thread is waiting on an object monitor -- <code>Object.wait</code>.
1157 </constant>
1158 <constant id="JVMTI_THREAD_STATE_PARKED" num="0x0200">
1159 Thread is parked, for example: <code>LockSupport.park</code>,
1160 <code>LockSupport.parkUtil</code> and <code>LockSupport.parkNanos</code>.
1161 </constant>
1162 <constant id="JVMTI_THREAD_STATE_SUSPENDED" num="0x100000">
1163 Thread suspended.
1164 <code>java.lang.Thread.suspend()</code>
1165 or a <jvmti/> suspend function
1166 (such as <functionlink id="SuspendThread"></functionlink>)
1167 has been called on the thread. If this bit
1168 is set, the other bits refer to the thread state before suspension.
1169 </constant>
1170 <constant id="JVMTI_THREAD_STATE_INTERRUPTED" num="0x200000">
1171 Thread has been interrupted.
1172 </constant>
1173 <constant id="JVMTI_THREAD_STATE_IN_NATIVE" num="0x400000">
1174 Thread is in native code--that is, a native method is running
1175 which has not called back into the VM or Java programming
1176 language code.
1177 <p/>
1178 This flag is not set when running VM compiled Java programming
1179 language code nor is it set when running VM code or
1180 VM support code. Native VM interface functions, such as JNI and
1181 <jvmti/> functions, may be implemented as VM code.
1182 </constant>
1183 <constant id="JVMTI_THREAD_STATE_VENDOR_1" num="0x10000000">
1184 Defined by VM vendor.
1185 </constant>
1186 <constant id="JVMTI_THREAD_STATE_VENDOR_2" num="0x20000000">
1187 Defined by VM vendor.
1188 </constant>
1189 <constant id="JVMTI_THREAD_STATE_VENDOR_3" num="0x40000000">
1190 Defined by VM vendor.
1191 </constant>
1192 </constants>
1193 The following definitions are used to convert <jvmti/> thread state
1194 to <code>java.lang.Thread.State</code> style states.
1195 <constants id="jvmtiJavaLangThreadState" label="java.lang.Thread.State Conversion Masks" kind="bits">
1196 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_MASK"
1197 num="JVMTI_THREAD_STATE_TERMINATED | JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_RUNNABLE | JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY | JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT">
1198 Mask the state with this before comparison
1199 </constant>
1200 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_NEW"
1201 num="0">
1202 <code>java.lang.Thread.State.NEW</code>
1203 </constant>
1204 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED"
1205 num="JVMTI_THREAD_STATE_TERMINATED">
1206 <code>java.lang.Thread.State.TERMINATED</code>
1207 </constant>
1208 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE"
1209 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_RUNNABLE">
1210 <code>java.lang.Thread.State.RUNNABLE</code>
1211 </constant>
1212 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED"
1213 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER">
1214 <code>java.lang.Thread.State.BLOCKED</code>
1215 </constant>
1216 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_WAITING"
1217 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY">
1218 <code>java.lang.Thread.State.WAITING</code>
1219 </constant>
1220 <constant id="JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING"
1221 num="JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT">
1222 <code>java.lang.Thread.State.TIMED_WAITING</code>
1223 </constant>
1224 </constants>
1225 <b>Rules</b>
1226 <p/>
1227 There can be no more than one answer to a question, although there can be no
1228 answer (because the answer is unknown, does not apply, or none of the answers is
1229 correct). An answer is set only when the enclosing answers match.
1230 That is, no more than one of
1231 <ul type="circle">
1232 <li><code>JVMTI_THREAD_STATE_RUNNABLE</code></li>
1233 <li><code>JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER</code></li>
1234 <li><code>JVMTI_THREAD_STATE_WAITING</code></li>
1235 </ul>
1236 can be set (a <tm>J2SE</tm> compliant implementation will always set
1237 one of these if <code>JVMTI_THREAD_STATE_ALIVE</code> is set).
1238 And if any of these are set, the enclosing answer
1239 <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
1240 No more than one of
1241 <ul type="circle">
1242 <li><code>JVMTI_THREAD_STATE_WAITING_INDEFINITELY</code></li>
1243 <li><code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code></li>
1244 </ul>
1245 can be set (a <tm>J2SE</tm> compliant implementation will always set
1246 one of these if <code>JVMTI_THREAD_STATE_WAITING</code> is set).
1247 And if either is set, the enclosing answers
1248 <code>JVMTI_THREAD_STATE_ALIVE</code> and
1249 <code>JVMTI_THREAD_STATE_WAITING</code> are set.
1250 No more than one of
1251 <ul type="circle">
1252 <li><code>JVMTI_THREAD_STATE_IN_OBJECT_WAIT</code></li>
1253 <li><code>JVMTI_THREAD_STATE_PARKED</code></li>
1254 <li><code>JVMTI_THREAD_STATE_SLEEPING</code></li>
1255 </ul>
1256 can be set. And if any of these is set, the enclosing answers
1257 <code>JVMTI_THREAD_STATE_ALIVE</code> and
1258 <code>JVMTI_THREAD_STATE_WAITING</code> are set.
1259 Also, if <code>JVMTI_THREAD_STATE_SLEEPING</code> is set,
1260 then <code>JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT</code> is set.
1261 If a state <i>A</i> is implemented using the mechanism of
1262 state <i>B</i> then it is state <i>A</i> which
1263 is returned by this function.
1264 For example, if <code>Thread.sleep(long)</code>
1265 is implemented using <code>Object.wait(long)</code>
1266 then it is still <code>JVMTI_THREAD_STATE_SLEEPING</code>
1267 which is returned.
1268 More than one of
1269 <ul type="circle">
1270 <li><code>JVMTI_THREAD_STATE_SUSPENDED</code></li>
1271 <li><code>JVMTI_THREAD_STATE_INTERRUPTED</code></li>
1272 <li><code>JVMTI_THREAD_STATE_IN_NATIVE</code></li>
1273 </ul>
1274 can be set, but if any is set,
1275 <code>JVMTI_THREAD_STATE_ALIVE</code> is set.
1276 <p/>
1277 And finally,
1278 <code>JVMTI_THREAD_STATE_TERMINATED</code> cannot be set unless
1279 <code>JVMTI_THREAD_STATE_ALIVE</code> is not set.
1280 <p/>
1281 The thread state representation is designed for extension in future versions
1282 of the specification; thread state values should be used accordingly, that is
1283 they should not be used as ordinals.
1284 Most queries can be made by testing a single bit, if use in a switch statement is desired,
1285 the state bits should be masked with the interesting bits.
1286 All bits not defined above are reserved for future use.
1287 A VM, compliant to the current specification, must set reserved bits to zero.
1288 An agent should ignore reserved bits --
1289 they should not be assumed to be zero and thus should not be included in comparisons.
1290 <p/>
1291 <b>Examples</b>
1292 <p/>
1293 Note that the values below exclude reserved and vendor bits.
1294 <p/>
1295 The state of a thread blocked at a <code>synchronized</code>-statement would be:
1296 <example>
1297 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER
1298 </example>
1299 The state of a thread which hasn't started yet would be:
1300 <example>
1301 0
1302 </example>
1303 The state of a thread at a <code>Object.wait(3000)</code> would be:
1304 <example>
1305 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_WAITING +
1306 JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT +
1307 JVMTI_THREAD_STATE_MONITOR_WAITING
1308 </example>
1309 The state of a thread suspended while runnable would be:
1310 <example>
1311 JVMTI_THREAD_STATE_ALIVE + JVMTI_THREAD_STATE_RUNNABLE + JVMTI_THREAD_STATE_SUSPENDED
1312 </example>
1313 <p/>
1314 <b>Testing the State</b>
1315 <p/>
1316 In most cases, the thread state can be determined by testing the one bit corresponding
1317 to that question. For example, the code to test if a thread is sleeping:
1318 <example>
1319 jint state;
1320 jvmtiError err;
1322 err = (*jvmti)->GetThreadState(jvmti, thread, &state);
1323 if (err == JVMTI_ERROR_NONE) {
1324 if (state & JVMTI_THREAD_STATE_SLEEPING) { ...
1325 </example>
1326 <p/>
1327 For waiting (that is, in <code>Object.wait</code>, parked, or sleeping) it would be:
1328 <example>
1329 if (state & JVMTI_THREAD_STATE_WAITING) { ...
1330 </example>
1331 For some states, more than one bit will need to be tested as is the case
1332 when testing if a thread has not yet been started:
1333 <example>
1334 if ((state & (JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_TERMINATED)) == 0) { ...
1335 </example>
1336 To distinguish timed from untimed <code>Object.wait</code>:
1337 <example>
1338 if (state & JVMTI_THREAD_STATE_IN_OBJECT_WAIT) {
1339 if (state & JVMTI_THREAD_STATE_WAITING_WITH_TIMEOUT) {
1340 printf("in Object.wait(long timeout)\n");
1341 } else {
1342 printf("in Object.wait()\n");
1343 }
1344 }
1345 </example>
1346 <p/>
1347 <b>Relationship to <code>java.lang.Thread.State</code></b>
1348 <p/>
1349 The thread state represented by <code>java.lang.Thread.State</code>
1350 returned from <code>java.lang.Thread.getState()</code> is a subset of the
1351 information returned from this function.
1352 The corresponding <code>java.lang.Thread.State</code> can be determined
1353 by using the provided conversion masks.
1354 For example, this returns the name of the <code>java.lang.Thread.State</code> thread state:
1355 <example>
1356 err = (*jvmti)->GetThreadState(jvmti, thread, &state);
1357 abortOnError(err);
1358 switch (state & JVMTI_JAVA_LANG_THREAD_STATE_MASK) {
1359 case JVMTI_JAVA_LANG_THREAD_STATE_NEW:
1360 return "NEW";
1361 case JVMTI_JAVA_LANG_THREAD_STATE_TERMINATED:
1362 return "TERMINATED";
1363 case JVMTI_JAVA_LANG_THREAD_STATE_RUNNABLE:
1364 return "RUNNABLE";
1365 case JVMTI_JAVA_LANG_THREAD_STATE_BLOCKED:
1366 return "BLOCKED";
1367 case JVMTI_JAVA_LANG_THREAD_STATE_WAITING:
1368 return "WAITING";
1369 case JVMTI_JAVA_LANG_THREAD_STATE_TIMED_WAITING:
1370 return "TIMED_WAITING";
1371 }
1372 </example>
1373 </description>
1374 <origin>new</origin>
1375 <capabilities>
1376 </capabilities>
1377 <parameters>
1378 <param id="thread">
1379 <jthread null="current" started="maybe" impl="noconvert"/>
1380 <description>
1381 The thread to query.
1382 </description>
1383 </param>
1384 <param id="thread_state_ptr">
1385 <outptr><jint/></outptr>
1386 <description>
1387 On return, points to state flags,
1388 as defined by the <internallink id="jvmtiThreadState">Thread State Flags</internallink>.
1389 </description>
1390 </param>
1391 </parameters>
1392 <errors>
1393 </errors>
1394 </function>
1396 <function id="GetCurrentThread" phase="start" num="18" since="1.1">
1397 <synopsis>Get Current Thread</synopsis>
1398 <description>
1399 Get the current thread.
1400 The current thread is the Java programming language thread which has called the function.
1401 <p/>
1402 Note that most <jvmti/> functions that take a thread
1403 as an argument will accept <code>NULL</code> to mean
1404 the current thread.
1405 </description>
1406 <origin>new</origin>
1407 <capabilities>
1408 </capabilities>
1409 <parameters>
1410 <param id="thread_ptr">
1411 <outptr><jthread/></outptr>
1412 <description>
1413 On return, points to the current thread.
1414 </description>
1415 </param>
1416 </parameters>
1417 <errors>
1418 </errors>
1419 </function>
1421 <function id="GetAllThreads" num="4">
1422 <synopsis>Get All Threads</synopsis>
1423 <description>
1424 Get all live threads.
1425 The threads are Java programming language threads;
1426 that is, threads that are attached to the VM.
1427 A thread is live if <code>java.lang.Thread.isAlive()</code>
1428 would return <code>true</code>, that is, the thread has
1429 been started and has not yet died.
1430 The universe of threads is determined by the context of the <jvmti/>
1431 environment, which typically is all threads attached to the VM.
1432 Note that this includes <jvmti/> agent threads
1433 (see <functionlink id="RunAgentThread"/>).
1434 </description>
1435 <origin>jvmdi</origin>
1436 <capabilities>
1437 </capabilities>
1438 <parameters>
1439 <param id="threads_count_ptr">
1440 <outptr><jint/></outptr>
1441 <description>
1442 On return, points to the number of running threads.
1443 </description>
1444 </param>
1445 <param id="threads_ptr">
1446 <allocbuf outcount="threads_count_ptr"><jthread/></allocbuf>
1447 <description>
1448 On return, points to an array of references, one
1449 for each running thread.
1450 </description>
1451 </param>
1452 </parameters>
1453 <errors>
1454 </errors>
1455 </function>
1457 <function id="SuspendThread" num="5">
1458 <synopsis>Suspend Thread</synopsis>
1459 <description>
1460 Suspend the specified thread. If the calling thread is specified,
1461 this function will not return until some other thread calls
1462 <functionlink id="ResumeThread"></functionlink>.
1463 If the thread is currently suspended, this function
1464 does nothing and returns an error.
1465 </description>
1466 <origin>jvmdi</origin>
1467 <capabilities>
1468 <required id="can_suspend"></required>
1469 </capabilities>
1470 <parameters>
1471 <param id="thread">
1472 <jthread null="current"/>
1473 <description>
1474 The thread to suspend.
1475 </description>
1476 </param>
1477 </parameters>
1478 <errors>
1479 <error id="JVMTI_ERROR_THREAD_SUSPENDED">
1480 Thread already suspended.
1481 </error>
1482 </errors>
1483 </function>
1485 <elide>
1486 <function id="SuspendAllThreads" num="101">
1487 <synopsis>Suspend All Threads</synopsis>
1488 <description>
1489 <issue>
1490 There has been no explicit call for this function, and it will
1491 thus be removed if there is no interest.
1492 </issue>
1493 Suspend all live threads except:
1494 <ul>
1495 <li>already suspended threads</li>
1496 <li>those listed in <paramlink id="except_list"></paramlink></li>
1497 <li>certain system (non application) threads, as determined
1498 by the VM implementation</li>
1499 </ul>
1500 The threads are Java programming language threads;
1501 native threads which are not attached to the VM are not
1502 Java programming language threads.
1503 A thread is live if <code>java.lang.Thread.isAlive()</code>
1504 would return <code>true</code>, that is, the thread has
1505 been started and has not yet died.
1506 The universe of threads is determined
1507 by the context of the <jvmti/>
1508 environment, which, typically, is all threads attached to the VM,
1509 except critical VM internal threads and <jvmti/> agent threads
1510 (see <functionlink id="RunAgentThread"/>).
1511 <p/>
1512 If the calling thread is specified,
1513 all other threads are suspended first then the caller thread is suspended -
1514 this function will not return until some other thread calls
1515 <functionlink id="ResumeThread"></functionlink>.
1516 <p/>
1517 The list of actually
1518 suspended threads is returned in
1519 <paramlink id="suspended_list_ptr"></paramlink>.
1520 Suspension is as defined in <functionlink id="SuspendThread"></functionlink>.
1521 <functionlink id="ResumeThreadList"></functionlink>
1522 can be used to resume the suspended threads.
1523 </description>
1524 <origin>new</origin>
1525 <capabilities>
1526 <required id="can_suspend"></required>
1527 </capabilities>
1528 <parameters>
1529 <param id="except_count">
1530 <jint min="0"/>
1531 <description>
1532 The number of threads in the list of threads not to be suspended.
1533 </description>
1534 </param>
1535 <param id="except_list">
1536 <inbuf incount="except_count">
1537 <jthread/>
1538 <nullok>not an error if <code>except_count == 0</code></nullok>
1539 </inbuf>
1540 <description>
1541 The list of threads not to be suspended.
1542 </description>
1543 </param>
1544 <param id="suspended_count_ptr">
1545 <outptr><jint/></outptr>
1546 <description>
1547 On return, points to the number of threads suspended by this call.
1548 </description>
1549 </param>
1550 <param id="suspended_list_ptr">
1551 <allocbuf outcount="suspended_count_ptr"><jthread/></allocbuf>
1552 <description>
1553 On return, points to an array of references, one
1554 for each thread suspended.
1555 </description>
1556 </param>
1557 </parameters>
1558 <errors>
1559 <error id="JVMTI_ERROR_INVALID_THREAD">
1560 A thread in <paramlink id="except_list"></paramlink> was invalid.
1561 </error>
1562 <error id="JVMTI_ERROR_NULL_POINTER">
1563 Both <paramlink id="except_list"></paramlink> was <code>NULL</code>
1564 and <paramlink id="except_count"></paramlink> was non-zero.
1565 </error>
1566 </errors>
1567 </function>
1568 </elide>
1570 <function id="SuspendThreadList" num="92">
1571 <synopsis>Suspend Thread List</synopsis>
1572 <description>
1573 Suspend the <paramlink id="request_count"></paramlink>
1574 threads specified in the
1575 <paramlink id="request_list"></paramlink> array.
1576 Threads may be resumed with
1577 <functionlink id="ResumeThreadList"></functionlink> or
1578 <functionlink id="ResumeThread"></functionlink>.
1579 If the calling thread is specified in the
1580 <paramlink id="request_list"></paramlink> array, this function will
1581 not return until some other thread resumes it.
1582 Errors encountered in the suspension of a thread
1583 are returned in the <paramlink id="results"></paramlink>
1584 array, <b>not</b> in the return value of this function.
1585 Threads that are currently suspended do not change state.
1586 </description>
1587 <origin>jvmdi</origin>
1588 <capabilities>
1589 <required id="can_suspend"></required>
1590 </capabilities>
1591 <parameters>
1592 <param id="request_count">
1593 <jint min="0"/>
1594 <description>
1595 The number of threads to suspend.
1596 </description>
1597 </param>
1598 <param id="request_list">
1599 <inbuf incount="request_count"><jthread/></inbuf>
1600 <description>
1601 The list of threads to suspend.
1602 </description>
1603 </param>
1604 <param id="results">
1605 <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1606 <description>
1607 An agent supplied array of
1608 <paramlink id="request_count"></paramlink> elements.
1609 On return, filled with the error code for
1610 the suspend of the corresponding thread.
1611 The error code will be
1612 <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1613 if the thread was suspended by this call.
1614 Possible error codes are those specified
1615 for <functionlink id="SuspendThread"></functionlink>.
1616 </description>
1617 </param>
1618 </parameters>
1619 <errors>
1620 </errors>
1621 </function>
1623 <function id="ResumeThread" num="6">
1624 <synopsis>Resume Thread</synopsis>
1625 <description>
1626 Resume a suspended thread.
1627 Any threads currently suspended through
1628 a <jvmti/> suspend function (eg.
1629 <functionlink id="SuspendThread"></functionlink>)
1630 or <code>java.lang.Thread.suspend()</code>
1631 will resume execution;
1632 all other threads are unaffected.
1633 </description>
1634 <origin>jvmdi</origin>
1635 <capabilities>
1636 <required id="can_suspend"></required>
1637 </capabilities>
1638 <parameters>
1639 <param id="thread">
1640 <jthread/>
1641 <description>
1642 The thread to resume.
1643 </description>
1644 </param>
1645 </parameters>
1646 <errors>
1647 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
1648 Thread was not suspended.
1649 </error>
1650 <error id="JVMTI_ERROR_INVALID_TYPESTATE">
1651 The state of the thread has been modified, and is now inconsistent.
1652 </error>
1653 </errors>
1654 </function>
1656 <function id="ResumeThreadList" num="93">
1657 <synopsis>Resume Thread List</synopsis>
1658 <description>
1659 Resume the <paramlink id="request_count"></paramlink>
1660 threads specified in the
1661 <paramlink id="request_list"></paramlink> array.
1662 Any thread suspended through
1663 a <jvmti/> suspend function (eg.
1664 <functionlink id="SuspendThreadList"></functionlink>)
1665 or <code>java.lang.Thread.suspend()</code>
1666 will resume execution.
1667 </description>
1668 <origin>jvmdi</origin>
1669 <capabilities>
1670 <required id="can_suspend"></required>
1671 </capabilities>
1672 <parameters>
1673 <param id="request_count">
1674 <jint min="0"/>
1675 <description>
1676 The number of threads to resume.
1677 </description>
1678 </param>
1679 <param id="request_list">
1680 <inbuf incount="request_count"><jthread/></inbuf>
1681 <description>
1682 The threads to resume.
1683 </description>
1684 </param>
1685 <param id="results">
1686 <outbuf incount="request_count"><enum>jvmtiError</enum></outbuf>
1687 <description>
1688 An agent supplied array of
1689 <paramlink id="request_count"></paramlink> elements.
1690 On return, filled with the error code for
1691 the resume of the corresponding thread.
1692 The error code will be
1693 <errorlink id="JVMTI_ERROR_NONE"></errorlink>
1694 if the thread was suspended by this call.
1695 Possible error codes are those specified
1696 for <functionlink id="ResumeThread"></functionlink>.
1697 </description>
1698 </param>
1699 </parameters>
1700 <errors>
1701 </errors>
1702 </function>
1704 <function id="StopThread" num="7">
1705 <synopsis>Stop Thread</synopsis>
1706 <description>
1707 Send the specified asynchronous exception to the specified thread
1708 (similar to <code>java.lang.Thread.stop</code>).
1709 Normally, this function is used to kill the specified thread with an
1710 instance of the exception <code>ThreadDeath</code>.
1711 </description>
1712 <origin>jvmdi</origin>
1713 <capabilities>
1714 <required id="can_signal_thread"></required>
1715 </capabilities>
1716 <parameters>
1717 <param id="thread">
1718 <jthread/>
1719 <description>
1720 The thread to stop.
1721 </description>
1722 </param>
1723 <param id="exception">
1724 <jobject/>
1725 <description>
1726 The asynchronous exception object.
1727 </description>
1728 </param>
1729 </parameters>
1730 <errors>
1731 </errors>
1732 </function>
1734 <function id="InterruptThread" num="8">
1735 <synopsis>Interrupt Thread</synopsis>
1736 <description>
1737 Interrupt the specified thread
1738 (similar to <code>java.lang.Thread.interrupt</code>).
1739 </description>
1740 <origin>jvmdi</origin>
1741 <capabilities>
1742 <required id="can_signal_thread"></required>
1743 </capabilities>
1744 <parameters>
1745 <param id="thread">
1746 <jthread impl="noconvert"/>
1747 <description>
1748 The thread to interrupt.
1749 </description>
1750 </param>
1751 </parameters>
1752 <errors>
1753 </errors>
1754 </function>
1756 <function id="GetThreadInfo" num="9">
1757 <synopsis>Get Thread Info</synopsis>
1758 <typedef id="jvmtiThreadInfo" label="Thread information structure">
1759 <field id="name">
1760 <allocfieldbuf><char/></allocfieldbuf>
1761 <description>
1762 The thread name, encoded as a
1763 <internallink id="mUTF">modified UTF-8</internallink> string.
1764 </description>
1765 </field>
1766 <field id="priority">
1767 <jint/>
1768 <description>
1769 The thread priority. See the thread priority constants:
1770 <datalink id="jvmtiThreadPriority"></datalink>.
1771 </description>
1772 </field>
1773 <field id="is_daemon">
1774 <jboolean/>
1775 <description>
1776 Is this a daemon thread?
1777 </description>
1778 </field>
1779 <field id="thread_group">
1780 <jthreadGroup/>
1781 <description>
1782 The thread group to which this thread belongs.
1783 <code>NULL</code> if the thread has died.
1784 </description>
1785 </field>
1786 <field id="context_class_loader">
1787 <jobject/>
1788 <description>
1789 The context class loader associated with this thread.
1790 </description>
1791 </field>
1792 </typedef>
1793 <description>
1794 Get thread information. The fields of the <datalink id="jvmtiThreadInfo"/> structure
1795 are filled in with details of the specified thread.
1796 </description>
1797 <origin>jvmdi</origin>
1798 <capabilities>
1799 </capabilities>
1800 <parameters>
1801 <param id="thread">
1802 <jthread null="current" impl="noconvert" started="maybe"/>
1803 <description>
1804 The thread to query.
1805 </description>
1806 </param>
1807 <param id="info_ptr">
1808 <outptr><struct>jvmtiThreadInfo</struct></outptr>
1809 <description>
1810 On return, filled with information describing the specified thread.
1811 <p/>
1812 For JDK 1.1 implementations that don't
1813 recognize context class loaders,
1814 the <code>context_class_loader</code> field will be NULL.
1815 </description>
1816 </param>
1817 </parameters>
1818 <errors>
1819 </errors>
1820 </function>
1822 <function id="GetOwnedMonitorInfo" num="10">
1823 <synopsis>Get Owned Monitor Info</synopsis>
1824 <description>
1825 Get information about the monitors owned by the
1826 specified thread.
1827 </description>
1828 <origin>jvmdiClone</origin>
1829 <capabilities>
1830 <required id="can_get_owned_monitor_info"></required>
1831 </capabilities>
1832 <parameters>
1833 <param id="thread">
1834 <jthread null="current"/>
1835 <description>
1836 The thread to query.
1837 </description>
1838 </param>
1839 <param id="owned_monitor_count_ptr">
1840 <outptr><jint/></outptr>
1841 <description>
1842 The number of monitors returned.
1843 </description>
1844 </param>
1845 <param id="owned_monitors_ptr">
1846 <allocbuf outcount="owned_monitor_count_ptr"><jobject/></allocbuf>
1847 <description>
1848 The array of owned monitors.
1849 </description>
1850 </param>
1851 </parameters>
1852 <errors>
1853 </errors>
1854 </function>
1856 <function id="GetOwnedMonitorStackDepthInfo" num="153" since="1.1">
1857 <synopsis>Get Owned Monitor Stack Depth Info</synopsis>
1858 <typedef id="jvmtiMonitorStackDepthInfo"
1859 label="Monitor stack depth information structure">
1860 <field id="monitor">
1861 <jobject/>
1862 <description>
1863 The owned monitor.
1864 </description>
1865 </field>
1866 <field id="stack_depth">
1867 <jint/>
1868 <description>
1869 The stack depth. Corresponds to the stack depth used in the
1870 <internallink id="stack">Stack Frame functions</internallink>.
1871 That is, zero is the current frame, one is the frame which
1872 called the current frame. And it is negative one if the
1873 implementation cannot determine the stack depth (e.g., for
1874 monitors acquired by JNI <code>MonitorEnter</code>).
1875 </description>
1876 </field>
1877 </typedef>
1878 <description>
1879 Get information about the monitors owned by the
1880 specified thread and the depth of the stack frame which locked them.
1881 </description>
1882 <origin>new</origin>
1883 <capabilities>
1884 <required id="can_get_owned_monitor_stack_depth_info"></required>
1885 </capabilities>
1886 <parameters>
1887 <param id="thread">
1888 <jthread null="current"/>
1889 <description>
1890 The thread to query.
1891 </description>
1892 </param>
1893 <param id="monitor_info_count_ptr">
1894 <outptr><jint/></outptr>
1895 <description>
1896 The number of monitors returned.
1897 </description>
1898 </param>
1899 <param id="monitor_info_ptr">
1900 <allocbuf outcount="owned_monitor_depth_count_ptr">
1901 <struct>jvmtiMonitorStackDepthInfo</struct>
1902 </allocbuf>
1903 <description>
1904 The array of owned monitor depth information.
1905 </description>
1906 </param>
1907 </parameters>
1908 <errors>
1909 </errors>
1910 </function>
1912 <function id="GetCurrentContendedMonitor" num="11">
1913 <synopsis>Get Current Contended Monitor</synopsis>
1914 <description>
1915 Get the object, if any, whose monitor the specified thread is waiting to
1916 enter or waiting to regain through <code>java.lang.Object.wait</code>.
1917 </description>
1918 <origin>jvmdi</origin>
1919 <capabilities>
1920 <required id="can_get_current_contended_monitor"></required>
1921 </capabilities>
1922 <parameters>
1923 <param id="thread">
1924 <jthread null="current"/>
1925 <description>
1926 The thread to query.
1927 </description>
1928 </param>
1929 <param id="monitor_ptr">
1930 <outptr><jobject/></outptr>
1931 <description>
1932 On return, filled with the current contended monitor, or
1933 NULL if there is none.
1934 </description>
1935 </param>
1936 </parameters>
1937 <errors>
1938 </errors>
1939 </function>
1941 <callback id="jvmtiStartFunction">
1942 <void/>
1943 <synopsis>Agent Start Function</synopsis>
1944 <description>
1945 Agent supplied callback function.
1946 This function is the entry point for an agent thread
1947 started with
1948 <functionlink id="RunAgentThread"></functionlink>.
1949 </description>
1950 <parameters>
1951 <param id="jvmti_env">
1952 <outptr>
1953 <struct>jvmtiEnv</struct>
1954 </outptr>
1955 <description>
1956 The <jvmti/> environment.
1957 </description>
1958 </param>
1959 <param id="jni_env">
1960 <outptr>
1961 <struct>JNIEnv</struct>
1962 </outptr>
1963 <description>
1964 The JNI environment.
1965 </description>
1966 </param>
1967 <param id="arg">
1968 <outptr>
1969 <void/>
1970 </outptr>
1971 <description>
1972 The <code>arg</code> parameter passed to
1973 <functionlink id="RunAgentThread"></functionlink>.
1974 </description>
1975 </param>
1976 </parameters>
1977 </callback>
1979 <function id="RunAgentThread" num="12">
1980 <synopsis>Run Agent Thread</synopsis>
1981 <description>
1982 Starts the execution of an agent thread. with the specified native function.
1983 The parameter <paramlink id="arg"></paramlink> is forwarded on to the
1984 <functionlink id="jvmtiStartFunction">start function</functionlink>
1985 (specified with <paramlink id="proc"></paramlink>) as its single argument.
1986 This function allows the creation of agent threads
1987 for handling communication with another process or for handling events
1988 without the need to load a special subclass of <code>java.lang.Thread</code> or
1989 implementer of <code>java.lang.Runnable</code>.
1990 Instead, the created thread can run entirely in native code.
1991 However, the created thread does require a newly created instance
1992 of <code>java.lang.Thread</code> (referenced by the argument <code>thread</code>) to
1993 which it will be associated.
1994 The thread object can be created with JNI calls.
1995 <p/>
1996 The following common thread priorities are provided for your convenience:
1997 <constants id="jvmtiThreadPriority" label="Thread Priority Constants" kind="const">
1998 <constant id="JVMTI_THREAD_MIN_PRIORITY" num="1">
1999 Minimum possible thread priority
2000 </constant>
2001 <constant id="JVMTI_THREAD_NORM_PRIORITY" num="5">
2002 Normal thread priority
2003 </constant>
2004 <constant id="JVMTI_THREAD_MAX_PRIORITY" num="10">
2005 Maximum possible thread priority
2006 </constant>
2007 </constants>
2008 <p/>
2009 The new thread is started as a daemon thread with the specified
2010 <paramlink id="priority"></paramlink>.
2011 If enabled, a <eventlink id="ThreadStart"/> event will be sent.
2012 <p/>
2013 Since the thread has been started, the thread will be live when this function
2014 returns, unless the thread has died immediately.
2015 <p/>
2016 The thread group of the thread is ignored -- specifically, the thread is not
2017 added to the thread group and the thread is not seen on queries of the thread
2018 group at either the Java programming language or <jvmti/> levels.
2019 <p/>
2020 The thread is not visible to Java programming language queries but is
2021 included in <jvmti/> queries (for example,
2022 <functionlink id="GetAllThreads"/> and
2023 <functionlink id="GetAllStackTraces"/>).
2024 <p/>
2025 Upon execution of <code>proc</code>, the new thread will be attached to the
2026 VM--see the JNI documentation on
2027 <externallink id="http://java.sun.com/javase/6/docs/technotes/guides/jni/spec/invocation.html#wp1060"
2028 >Attaching to the VM</externallink>.
2029 </description>
2030 <origin>jvmdiClone</origin>
2031 <capabilities>
2032 </capabilities>
2033 <parameters>
2034 <param id="thread">
2035 <jthread impl="noconvert" started="no"/>
2036 <description>
2037 The thread to run.
2038 </description>
2039 </param>
2040 <param id="proc">
2041 <ptrtype>
2042 <struct>jvmtiStartFunction</struct>
2043 </ptrtype>
2044 <description>
2045 The start function.
2046 </description>
2047 </param>
2048 <param id="arg">
2049 <inbuf>
2050 <void/>
2051 <nullok><code>NULL</code> is passed to the start function</nullok>
2052 </inbuf>
2053 <description>
2054 The argument to the start function.
2055 </description>
2056 </param>
2057 <param id="priority">
2058 <jint/>
2059 <description>
2060 The priority of the started thread. Any thread
2061 priority allowed by <code>java.lang.Thread.setPriority</code> can be used including
2062 those in <datalink id="jvmtiThreadPriority"></datalink>.
2063 </description>
2064 </param>
2065 </parameters>
2066 <errors>
2067 <error id="JVMTI_ERROR_INVALID_PRIORITY">
2068 <paramlink id="priority"/> is less than
2069 <datalink id="JVMTI_THREAD_MIN_PRIORITY"/>
2070 or greater than
2071 <datalink id="JVMTI_THREAD_MAX_PRIORITY"/>
2072 </error>
2073 </errors>
2074 </function>
2076 <function id="SetThreadLocalStorage" jkernel="yes" impl="notrace" phase="start" num="103">
2077 <synopsis>Set Thread Local Storage</synopsis>
2078 <description>
2079 The VM stores a pointer value associated with each environment-thread
2080 pair. This pointer value is called <i>thread-local storage</i>.
2081 This value is <code>NULL</code> unless set with this function.
2082 Agents can allocate memory in which they store thread specific
2083 information. By setting thread-local storage it can then be
2084 accessed with
2085 <functionlink id="GetThreadLocalStorage"></functionlink>.
2086 <p/>
2087 This function is called by the agent to set the value of the <jvmti/>
2088 thread-local storage. <jvmti/> supplies to the agent a pointer-size
2089 thread-local storage that can be used to record per-thread
2090 information.
2091 </description>
2092 <origin>jvmpi</origin>
2093 <capabilities>
2094 </capabilities>
2095 <parameters>
2096 <param id="thread">
2097 <jthread null="current"/>
2098 <description>
2099 Store to this thread.
2100 </description>
2101 </param>
2102 <param id="data">
2103 <inbuf>
2104 <void/>
2105 <nullok>value is set to <code>NULL</code></nullok>
2106 </inbuf>
2107 <description>
2108 The value to be entered into the thread-local storage.
2109 </description>
2110 </param>
2111 </parameters>
2112 <errors>
2113 </errors>
2114 </function>
2116 <function id="GetThreadLocalStorage" jkernel="yes" impl="innative notrace" phase="start" num="102">
2117 <synopsis>Get Thread Local Storage</synopsis>
2118 <description>
2119 Called by the agent to get the value of the <jvmti/> thread-local
2120 storage.
2121 </description>
2122 <origin>jvmpi</origin>
2123 <capabilities>
2124 </capabilities>
2125 <parameters>
2126 <param id="thread">
2127 <jthread null="current" impl="noconvert"/>
2128 <description>
2129 Retrieve from this thread.
2130 </description>
2131 </param>
2132 <param id="data_ptr">
2133 <agentbuf><void/></agentbuf>
2134 <description>
2135 Pointer through which the value of the thread local
2136 storage is returned.
2137 If thread-local storage has not been set with
2138 <functionlink id="SetThreadLocalStorage"></functionlink> the returned
2139 pointer is <code>NULL</code>.
2140 </description>
2141 </param>
2142 </parameters>
2143 <errors>
2144 </errors>
2145 </function>
2147 </category>
2149 <category id="thread_groups" label="Thread Group">
2150 <intro>
2151 </intro>
2153 <function id="GetTopThreadGroups" num="13">
2154 <synopsis>Get Top Thread Groups</synopsis>
2155 <description>
2156 Return all top-level (parentless) thread groups in the VM.
2157 </description>
2158 <origin>jvmdi</origin>
2159 <capabilities>
2160 </capabilities>
2161 <parameters>
2162 <param id="group_count_ptr">
2163 <outptr><jint/></outptr>
2164 <description>
2165 On return, points to the number of top-level thread groups.
2166 </description>
2167 </param>
2168 <param id="groups_ptr">
2169 <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2170 <description>
2171 On return, refers to a pointer to the top-level thread group array.
2172 </description>
2173 </param>
2174 </parameters>
2175 <errors>
2176 </errors>
2177 </function>
2179 <function id="GetThreadGroupInfo" num="14">
2180 <synopsis>Get Thread Group Info</synopsis>
2181 <typedef id="jvmtiThreadGroupInfo" label="Thread group information structure">
2182 <field id="parent">
2183 <jthreadGroup/>
2184 <description>
2185 The parent thread group.
2186 </description>
2187 </field>
2188 <field id="name">
2189 <allocfieldbuf><char/></allocfieldbuf>
2190 <description>
2191 The thread group's name, encoded as a
2192 <internallink id="mUTF">modified UTF-8</internallink> string.
2193 </description>
2194 </field>
2195 <field id="max_priority">
2196 <jint/>
2197 <description>
2198 The maximum priority for this thread group.
2199 </description>
2200 </field>
2201 <field id="is_daemon">
2202 <jboolean/>
2203 <description>
2204 Is this a daemon thread group?
2205 </description>
2206 </field>
2207 </typedef>
2208 <description>
2209 Get information about the thread group. The fields of the
2210 <functionlink id="jvmtiThreadGroupInfo"></functionlink> structure
2211 are filled in with details of the specified thread group.
2212 </description>
2213 <origin>jvmdi</origin>
2214 <capabilities>
2215 </capabilities>
2216 <parameters>
2217 <param id="group">
2218 <jthreadGroup/>
2219 <description>
2220 The thread group to query.
2221 </description>
2222 </param>
2223 <param id="info_ptr">
2224 <outptr><struct>jvmtiThreadGroupInfo</struct></outptr>
2225 <description>
2226 On return, filled with information describing the specified
2227 thread group.
2228 </description>
2229 </param>
2230 </parameters>
2231 <errors>
2232 </errors>
2233 </function>
2235 <function id="GetThreadGroupChildren" num="15">
2236 <synopsis>Get Thread Group Children</synopsis>
2237 <description>
2238 Get the live threads and active subgroups in this thread group.
2239 </description>
2240 <origin>jvmdi</origin>
2241 <capabilities>
2242 </capabilities>
2243 <parameters>
2244 <param id="group">
2245 <jthreadGroup/>
2246 <description>
2247 The group to query.
2248 </description>
2249 </param>
2250 <param id="thread_count_ptr">
2251 <outptr><jint/></outptr>
2252 <description>
2253 On return, points to the number of live threads in this thread group.
2254 </description>
2255 </param>
2256 <param id="threads_ptr">
2257 <allocbuf outcount="thread_count_ptr"><jthread/></allocbuf>
2258 <description>
2259 On return, points to an array of the live threads in this thread group.
2260 </description>
2261 </param>
2262 <param id="group_count_ptr">
2263 <outptr><jint/></outptr>
2264 <description>
2265 On return, points to the number of active child thread groups
2266 </description>
2267 </param>
2268 <param id="groups_ptr">
2269 <allocbuf outcount="group_count_ptr"><jthreadGroup/></allocbuf>
2270 <description>
2271 On return, points to an array of the active child thread groups.
2272 </description>
2273 </param>
2274 </parameters>
2275 <errors>
2276 </errors>
2277 </function>
2278 </category>
2280 <category id="stack" label="Stack Frame">
2281 <intro>
2282 These functions provide information about the stack of a thread.
2283 Stack frames are referenced by depth.
2284 The frame at depth zero is the current frame.
2285 <p/>
2286 Stack frames are as described in
2287 <vmspec chapter="3.6"/>,
2288 That is, they correspond to method
2289 invocations (including native methods) but do not correspond to platform native or
2290 VM internal frames.
2291 <p/>
2292 A <jvmti/> implementation may use method invocations to launch a thread and
2293 the corresponding frames may be included in the stack as presented by these functions --
2294 that is, there may be frames shown
2295 deeper than <code>main()</code> and <code>run()</code>.
2296 However this presentation must be consistent across all <jvmti/> functionality which
2297 uses stack frames or stack depth.
2298 </intro>
2300 <typedef id="jvmtiFrameInfo" label="Stack frame information structure">
2301 <description>
2302 Information about a stack frame is returned in this structure.
2303 </description>
2304 <field id="method">
2305 <jmethodID/>
2306 <description>
2307 The method executing in this frame.
2308 </description>
2309 </field>
2310 <field id="location">
2311 <jlocation/>
2312 <description>
2313 The index of the instruction executing in this frame.
2314 <code>-1</code> if the frame is executing a native method.
2315 </description>
2316 </field>
2317 </typedef>
2319 <typedef id="jvmtiStackInfo" label="Stack information structure">
2320 <description>
2321 Information about a set of stack frames is returned in this structure.
2322 </description>
2323 <field id="thread">
2324 <jthread/>
2325 <description>
2326 On return, the thread traced.
2327 </description>
2328 </field>
2329 <field id="state">
2330 <jint/>
2331 <description>
2332 On return, the thread state. See <functionlink id="GetThreadState"></functionlink>.
2333 </description>
2334 </field>
2335 <field id="frame_buffer">
2336 <outbuf incount="max_frame_count">
2337 <struct>jvmtiFrameInfo</struct>
2338 </outbuf>
2339 <description>
2340 On return, this agent allocated buffer is filled
2341 with stack frame information.
2342 </description>
2343 </field>
2344 <field id="frame_count">
2345 <jint/>
2346 <description>
2347 On return, the number of records filled into
2348 <code>frame_buffer</code>.
2349 This will be
2350 min(<code>max_frame_count</code>, <i>stackDepth</i>).
2351 </description>
2352 </field>
2353 </typedef>
2355 <function id="GetStackTrace" num="104">
2356 <synopsis>Get Stack Trace</synopsis>
2357 <description>
2358 Get information about the stack of a thread.
2359 If <paramlink id="max_frame_count"></paramlink> is less than the depth of the stack,
2360 the <paramlink id="max_frame_count"></paramlink> topmost frames are returned,
2361 otherwise the entire stack is returned.
2362 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2363 <p/>
2364 The following example causes up to five of the topmost frames
2365 to be returned and (if there are any frames) the currently
2366 executing method name to be printed.
2367 <example>
2368 jvmtiFrameInfo frames[5];
2369 jint count;
2370 jvmtiError err;
2372 err = (*jvmti)->GetStackTrace(jvmti, aThread, 0, 5,
2373 &frames, &count);
2374 if (err == JVMTI_ERROR_NONE && count >= 1) {
2375 char *methodName;
2376 err = (*jvmti)->GetMethodName(jvmti, frames[0].method,
2377 &methodName, NULL);
2378 if (err == JVMTI_ERROR_NONE) {
2379 printf("Executing method: %s", methodName);
2380 }
2381 }
2382 </example>
2383 <todo>
2384 check example code.
2385 </todo>
2386 <p/>
2387 The <paramlink id="thread"></paramlink> need not be suspended
2388 to call this function.
2389 <p/>
2390 The <functionlink id="GetLineNumberTable"></functionlink>
2391 function can be used to map locations to line numbers. Note that
2392 this mapping can be done lazily.
2393 </description>
2394 <origin>jvmpi</origin>
2395 <capabilities>
2396 </capabilities>
2397 <parameters>
2398 <param id="thread">
2399 <jthread null="current"/>
2400 <description>
2401 Fetch the stack trace of this thread.
2402 </description>
2403 </param>
2404 <param id="start_depth">
2405 <jint/>
2406 <description>
2407 Begin retrieving frames at this depth.
2408 If non-negative, count from the current frame,
2409 the first frame retrieved is at depth <code>start_depth</code>.
2410 For example, if zero, start from the current frame; if one, start from the
2411 caller of the current frame; if two, start from the caller of the
2412 caller of the current frame; and so on.
2413 If negative, count from below the oldest frame,
2414 the first frame retrieved is at depth <i>stackDepth</i><code> + start_depth</code>,
2415 where <i>stackDepth</i> is the count of frames on the stack.
2416 For example, if negative one, only the oldest frame is retrieved;
2417 if negative two, start from the frame called by the oldest frame.
2418 </description>
2419 </param>
2420 <param id="max_frame_count">
2421 <jint min="0"/>
2422 <description>
2423 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2424 </description>
2425 </param>
2426 <param id="frame_buffer">
2427 <outbuf incount="max_frame_count" outcount="count_ptr">
2428 <struct>jvmtiFrameInfo</struct>
2429 </outbuf>
2430 <description>
2431 On return, this agent allocated buffer is filled
2432 with stack frame information.
2433 </description>
2434 </param>
2435 <param id="count_ptr">
2436 <outptr><jint/></outptr>
2437 <description>
2438 On return, points to the number of records filled in.
2439 For non-negative <code>start_depth</code>, this will be
2440 min(<code>max_frame_count</code>, <i>stackDepth</i><code> - start_depth</code>).
2441 For negative <code>start_depth</code>, this will be
2442 min(<code>max_frame_count</code>, <code>-start_depth</code>).
2443 </description>
2444 </param>
2445 </parameters>
2446 <errors>
2447 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
2448 <paramlink id="start_depth"/> is positive and greater than or equal to <i>stackDepth</i>.
2449 Or <paramlink id="start_depth"/> is negative and less than <i>-stackDepth</i>.
2450 </error>
2451 </errors>
2452 </function>
2455 <function id="GetAllStackTraces" num="100">
2456 <synopsis>Get All Stack Traces</synopsis>
2457 <description>
2458 Get information about the stacks of all live threads
2459 (including <internallink id="RunAgentThread">agent threads</internallink>).
2460 If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2461 the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2462 otherwise the entire stack is returned.
2463 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2464 <p/>
2465 All stacks are collected simultaneously, that is, no changes will occur to the
2466 thread state or stacks between the sampling of one thread and the next.
2467 The threads need not be suspended.
2469 <example>
2470 jvmtiStackInfo *stack_info;
2471 jint thread_count;
2472 int ti;
2473 jvmtiError err;
2475 err = (*jvmti)->GetAllStackTraces(jvmti, MAX_FRAMES, &stack_info, &thread_count);
2476 if (err != JVMTI_ERROR_NONE) {
2477 ...
2478 }
2479 for (ti = 0; ti < thread_count; ++ti) {
2480 jvmtiStackInfo *infop = &stack_info[ti];
2481 jthread thread = infop->thread;
2482 jint state = infop->state;
2483 jvmtiFrameInfo *frames = infop->frame_buffer;
2484 int fi;
2486 myThreadAndStatePrinter(thread, state);
2487 for (fi = 0; fi < infop->frame_count; fi++) {
2488 myFramePrinter(frames[fi].method, frames[fi].location);
2489 }
2490 }
2491 /* this one Deallocate call frees all data allocated by GetAllStackTraces */
2492 err = (*jvmti)->Deallocate(jvmti, stack_info);
2493 </example>
2494 <todo>
2495 check example code.
2496 </todo>
2498 </description>
2499 <origin>new</origin>
2500 <capabilities>
2501 </capabilities>
2502 <parameters>
2503 <param id="max_frame_count">
2504 <jint min="0"/>
2505 <description>
2506 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2507 </description>
2508 </param>
2509 <param id="stack_info_ptr">
2510 <allocbuf>
2511 <struct>jvmtiStackInfo</struct>
2512 </allocbuf>
2513 <description>
2514 On return, this buffer is filled
2515 with stack information for each thread.
2516 The number of <datalink id="jvmtiStackInfo"/> records is determined
2517 by <paramlink id="thread_count_ptr"/>.
2518 <p/>
2519 Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2520 buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2521 These buffers must not be separately deallocated.
2522 </description>
2523 </param>
2524 <param id="thread_count_ptr">
2525 <outptr><jint/></outptr>
2526 <description>
2527 The number of threads traced.
2528 </description>
2529 </param>
2530 </parameters>
2531 <errors>
2532 </errors>
2533 </function>
2535 <function id="GetThreadListStackTraces" num="101">
2536 <synopsis>Get Thread List Stack Traces</synopsis>
2537 <description>
2538 Get information about the stacks of the supplied threads.
2539 If <paramlink id="max_frame_count"/> is less than the depth of a stack,
2540 the <paramlink id="max_frame_count"/> topmost frames are returned for that thread,
2541 otherwise the entire stack is returned.
2542 The topmost frames, those most recently invoked, are at the beginning of the returned buffer.
2543 <p/>
2544 All stacks are collected simultaneously, that is, no changes will occur to the
2545 thread state or stacks between the sampling one thread and the next.
2546 The threads need not be suspended.
2547 <p/>
2548 If a thread has not yet started or terminates before the stack information is collected,
2549 a zero length stack (<datalink id="jvmtiStackInfo.frame_count"/> will be zero)
2550 will be returned and the thread <datalink id="jvmtiStackInfo.state"/> can be checked.
2551 <p/>
2552 See the example for the similar function
2553 <functionlink id="GetAllStackTraces"/>.
2554 </description>
2555 <origin>new</origin>
2556 <capabilities>
2557 </capabilities>
2558 <parameters>
2559 <param id="thread_count">
2560 <jint min="0"/>
2561 <description>
2562 The number of threads to trace.
2563 </description>
2564 </param>
2565 <param id="thread_list">
2566 <inbuf incount="thread_count"><jthread/></inbuf>
2567 <description>
2568 The list of threads to trace.
2569 </description>
2570 </param>
2571 <param id="max_frame_count">
2572 <jint min="0"/>
2573 <description>
2574 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve per thread.
2575 </description>
2576 </param>
2577 <param id="stack_info_ptr">
2578 <allocbuf outcount="thread_count">
2579 <struct>jvmtiStackInfo</struct>
2580 </allocbuf>
2581 <description>
2582 On return, this buffer is filled
2583 with stack information for each thread.
2584 The number of <datalink id="jvmtiStackInfo"/> records is determined
2585 by <paramlink id="thread_count"/>.
2586 <p/>
2587 Note that this buffer is allocated to include the <datalink id="jvmtiFrameInfo"/>
2588 buffers pointed to by <datalink id="jvmtiStackInfo.frame_buffer"/>.
2589 These buffers must not be separately deallocated.
2590 </description>
2591 </param>
2592 </parameters>
2593 <errors>
2594 <error id="JVMTI_ERROR_INVALID_THREAD">
2595 An element in <paramlink id="thread_list"/> is not a thread object.
2596 </error>
2597 </errors>
2598 </function>
2600 <elide>
2601 <function id="AsyncGetStackTrace" num="1000">
2602 <synopsis>Get Stack Trace--Asynchronous</synopsis>
2603 <description>
2604 Get information about the entire stack of a thread (or a sub-section of it).
2605 This is the asynchronous version of <functionlink id="GetStackTrace"></functionlink>
2606 and is reentrant and safe to call
2607 from asynchronous signal handlers.
2608 The stack trace is returned only for the calling thread.
2609 <p/>
2610 The <functionlink id="GetLineNumberTable"></functionlink>
2611 function can be used to map locations to line numbers. Note that
2612 this mapping can be done lazily.
2613 </description>
2614 <origin>jvmpi</origin>
2615 <capabilities>
2616 <required id="can_get_async_stack_trace"></required>
2617 <capability id="can_show_JVM_spec_async_frames">
2618 If <code>false</code>,
2619 <paramlink id="use_java_stack"></paramlink>
2620 must be <code>false</code>.
2621 </capability>
2622 </capabilities>
2623 <parameters>
2624 <param id="use_java_stack">
2625 <jboolean/>
2626 <description>
2627 Return the stack showing <vmspec/>
2628 model of the stack;
2629 otherwise, show the internal representation of the stack with
2630 inlined and optimized methods missing. If the virtual machine
2631 is using the <i>Java Virtual Machine Specification</i> stack model
2632 internally, this flag is ignored.
2633 </description>
2634 </param>
2635 <param id="max_count">
2636 <jint min="0"/>
2637 <description>
2638 The maximum number of <datalink id="jvmtiFrameInfo"/> records to retrieve.
2639 Retrieve this many unless the stack depth is less than <code>max_count</code>.
2640 </description>
2641 </param>
2642 <param id="frame_buffer">
2643 <outbuf incount="max_count" outcount="count_ptr">
2644 <struct>jvmtiFrameInfo</struct>
2645 <nullok>this information is not returned</nullok>
2646 </outbuf>
2647 <description>
2648 The agent passes in a buffer
2649 large enough to hold <code>max_count</code> records of
2650 <datalink id="jvmtiFrameInfo"></datalink>. This buffer must be
2651 pre-allocated by the agent.
2652 </description>
2653 </param>
2654 <param id="count_ptr">
2655 <outptr><jint/></outptr>
2656 <description>
2657 On return, points to the number of records filled in..
2658 </description>
2659 </param>
2660 </parameters>
2661 <errors>
2662 <error id="JVMTI_ERROR_UNATTACHED_THREAD">
2663 The thread being used to call this function is not attached
2664 to the virtual machine. Calls must be made from attached threads.
2665 </error>
2666 </errors>
2667 </function>
2668 </elide>
2670 <function id="GetFrameCount" num="16">
2671 <synopsis>Get Frame Count</synopsis>
2672 <description>
2673 Get the number of frames currently in the specified thread's call stack.
2674 <p/>
2675 If this function is called for a thread actively executing bytecodes (for example,
2676 not the current thread and not suspended), the information returned is transient.
2677 </description>
2678 <origin>jvmdi</origin>
2679 <capabilities>
2680 </capabilities>
2681 <parameters>
2682 <param id="thread">
2683 <jthread null="current"/>
2684 <description>
2685 The thread to query.
2686 </description>
2687 </param>
2688 <param id="count_ptr">
2689 <outptr><jint/></outptr>
2690 <description>
2691 On return, points to the number of frames in the call stack.
2692 </description>
2693 </param>
2694 </parameters>
2695 <errors>
2696 </errors>
2697 </function>
2699 <function id="PopFrame" num="80">
2700 <synopsis>Pop Frame</synopsis>
2701 <description>
2702 Pop the current frame of <code>thread</code>'s stack.
2703 Popping a frame takes you to the previous frame.
2704 When the thread is resumed, the execution
2705 state of the thread is reset to the state
2706 immediately before the called method was invoked.
2707 That is (using <vmspec/> terminology):
2708 <ul>
2709 <li>the current frame is discarded as the previous frame becomes the current one</li>
2710 <li>the operand stack is restored--the argument values are added back
2711 and if the invoke was not <code>invokestatic</code>,
2712 <code>objectref</code> is added back as well</li>
2713 <li>the Java virtual machine PC is restored to the opcode
2714 of the invoke instruction</li>
2715 </ul>
2716 Note however, that any changes to the arguments, which
2717 occurred in the called method, remain;
2718 when execution continues, the first instruction to
2719 execute will be the invoke.
2720 <p/>
2721 Between calling <code>PopFrame</code> and resuming the
2722 thread the state of the stack is undefined.
2723 To pop frames beyond the first,
2724 these three steps must be repeated:
2725 <ul>
2726 <li>suspend the thread via an event (step, breakpoint, ...)</li>
2727 <li>call <code>PopFrame</code></li>
2728 <li>resume the thread</li>
2729 </ul>
2730 <p/>
2731 A lock acquired by calling the called method
2732 (if it is a <code>synchronized</code> method)
2733 and locks acquired by entering <code>synchronized</code>
2734 blocks within the called method are released.
2735 Note: this does not apply to native locks or
2736 <code>java.util.concurrent.locks</code> locks.
2737 <p/>
2738 Finally blocks are not executed.
2739 <p/>
2740 Changes to global state are not addressed and thus remain changed.
2741 <p/>
2742 The specified thread must be suspended (which implies it cannot be the current thread).
2743 <p/>
2744 Both the called method and calling method must be non-native Java programming
2745 language methods.
2746 <p/>
2747 No <jvmti/> events are generated by this function.
2748 </description>
2749 <origin>jvmdi</origin>
2750 <capabilities>
2751 <required id="can_pop_frame"></required>
2752 </capabilities>
2753 <parameters>
2754 <param id="thread">
2755 <jthread/>
2756 <description>
2757 The thread whose current frame is to be popped.
2758 </description>
2759 </param>
2760 </parameters>
2761 <errors>
2762 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2763 Called or calling method is a native method.
2764 The implementation is unable to pop this frame.
2765 </error>
2766 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2767 Thread was not suspended.
2768 </error>
2769 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
2770 There are less than two stack frames on the call stack.
2771 </error>
2772 </errors>
2773 </function>
2775 <function id="GetFrameLocation" num="19">
2776 <synopsis>Get Frame Location</synopsis>
2777 <description>
2778 <p/>
2779 For a Java programming language frame, return the location of the instruction
2780 currently executing.
2781 </description>
2782 <origin>jvmdiClone</origin>
2783 <capabilities>
2784 </capabilities>
2785 <parameters>
2786 <param id="thread">
2787 <jthread null="current" frame="frame"/>
2788 <description>
2789 The thread of the frame to query.
2790 </description>
2791 </param>
2792 <param id="depth">
2793 <jframeID thread="thread"/>
2794 <description>
2795 The depth of the frame to query.
2796 </description>
2797 </param>
2798 <param id="method_ptr">
2799 <outptr><jmethodID/></outptr>
2800 <description>
2801 On return, points to the method for the current location.
2802 </description>
2803 </param>
2804 <param id="location_ptr">
2805 <outptr><jlocation/></outptr>
2806 <description>
2807 On return, points to the index of the currently
2808 executing instruction.
2809 Is set to <code>-1</code> if the frame is executing
2810 a native method.
2811 </description>
2812 </param>
2813 </parameters>
2814 <errors>
2815 </errors>
2816 </function>
2818 <function id="NotifyFramePop" num="20">
2819 <synopsis>Notify Frame Pop</synopsis>
2820 <description>
2821 When the frame that is currently at <paramlink id="depth"></paramlink>
2822 is popped from the stack, generate a
2823 <eventlink id="FramePop"></eventlink> event. See the
2824 <eventlink id="FramePop"></eventlink> event for details.
2825 Only frames corresponding to non-native Java programming language
2826 methods can receive notification.
2827 <p/>
2828 The specified thread must either be the current thread
2829 or the thread must be suspended.
2830 </description>
2831 <origin>jvmdi</origin>
2832 <capabilities>
2833 <required id="can_generate_frame_pop_events"></required>
2834 </capabilities>
2835 <parameters>
2836 <param id="thread">
2837 <jthread null="current" frame="depth"/>
2838 <description>
2839 The thread of the frame for which the frame pop event will be generated.
2840 </description>
2841 </param>
2842 <param id="depth">
2843 <jframeID thread="thread"/>
2844 <description>
2845 The depth of the frame for which the frame pop event will be generated.
2846 </description>
2847 </param>
2848 </parameters>
2849 <errors>
2850 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2851 The frame at <code>depth</code> is executing a
2852 native method.
2853 </error>
2854 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2855 Thread was not suspended and was not the current thread.
2856 </error>
2857 </errors>
2858 </function>
2860 </category>
2862 <category id="ForceEarlyReturn" label="Force Early Return">
2863 <intro>
2864 These functions allow an agent to force a method
2865 to return at any point during its execution.
2866 The method which will return early is referred to as the <i>called method</i>.
2867 The called method is the current method
2868 (as defined by
2869 <vmspec chapter="3.6"/>)
2870 for the specified thread at
2871 the time the function is called.
2872 <p/>
2873 The specified thread must be suspended or must be the current thread.
2874 The return occurs when execution of Java programming
2875 language code is resumed on this thread.
2876 Between calling one of these functions and resumption
2877 of thread execution, the state of the stack is undefined.
2878 <p/>
2879 No further instructions are executed in the called method.
2880 Specifically, finally blocks are not executed.
2881 Note: this can cause inconsistent states in the application.
2882 <p/>
2883 A lock acquired by calling the called method
2884 (if it is a <code>synchronized</code> method)
2885 and locks acquired by entering <code>synchronized</code>
2886 blocks within the called method are released.
2887 Note: this does not apply to native locks or
2888 <code>java.util.concurrent.locks</code> locks.
2889 <p/>
2890 Events, such as <eventlink id="MethodExit"></eventlink>,
2891 are generated as they would be in a normal return.
2892 <p/>
2893 The called method must be a non-native Java programming
2894 language method.
2895 Forcing return on a thread with only one frame on the
2896 stack causes the thread to exit when resumed.
2897 </intro>
2899 <function id="ForceEarlyReturnObject" num="81" since="1.1">
2900 <synopsis>Force Early Return - Object</synopsis>
2901 <description>
2902 This function can be used to return from a method whose
2903 result type is <code>Object</code>
2904 or a subclass of <code>Object</code>.
2905 </description>
2906 <origin>new</origin>
2907 <capabilities>
2908 <required id="can_force_early_return"></required>
2909 </capabilities>
2910 <parameters>
2911 <param id="thread">
2912 <jthread null="current"/>
2913 <description>
2914 The thread whose current frame is to return early.
2915 </description>
2916 </param>
2917 <param id="value">
2918 <jobject/>
2919 <description>
2920 The return value for the called frame.
2921 An object or <code>NULL</code>.
2922 </description>
2923 </param>
2924 </parameters>
2925 <errors>
2926 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2927 Attempted to return early from a frame
2928 corresponding to a native method.
2929 Or the implementation is unable to provide
2930 this functionality on this frame.
2931 </error>
2932 <error id="JVMTI_ERROR_TYPE_MISMATCH">
2933 The result type of the called method is not
2934 <code>Object</code> or a subclass of <code>Object</code>.
2935 </error>
2936 <error id="JVMTI_ERROR_TYPE_MISMATCH">
2937 The supplied <paramlink id="value"/> is not compatible with the
2938 result type of the called method.
2939 </error>
2940 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2941 Thread was not the current thread and was not suspended.
2942 </error>
2943 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
2944 There are no more frames on the call stack.
2945 </error>
2946 </errors>
2947 </function>
2949 <function id="ForceEarlyReturnInt" num="82" since="1.1">
2950 <synopsis>Force Early Return - Int</synopsis>
2951 <description>
2952 This function can be used to return from a method whose
2953 result type is <code>int</code>, <code>short</code>,
2954 <code>char</code>, <code>byte</code>, or
2955 <code>boolean</code>.
2956 </description>
2957 <origin>new</origin>
2958 <capabilities>
2959 <required id="can_force_early_return"></required>
2960 </capabilities>
2961 <parameters>
2962 <param id="thread">
2963 <jthread null="current"/>
2964 <description>
2965 The thread whose current frame is to return early.
2966 </description>
2967 </param>
2968 <param id="value">
2969 <jint/>
2970 <description>
2971 The return value for the called frame.
2972 </description>
2973 </param>
2974 </parameters>
2975 <errors>
2976 <error id="JVMTI_ERROR_OPAQUE_FRAME">
2977 Attempted to return early from a frame
2978 corresponding to a native method.
2979 Or the implementation is unable to provide
2980 this functionality on this frame.
2981 </error>
2982 <error id="JVMTI_ERROR_TYPE_MISMATCH">
2983 The result type of the called method is not
2984 <code>int</code>, <code>short</code>,
2985 <code>char</code>, <code>byte</code>, or
2986 <code>boolean</code>.
2987 </error>
2988 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
2989 Thread was not the current thread and was not suspended.
2990 </error>
2991 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
2992 There are no frames on the call stack.
2993 </error>
2994 </errors>
2995 </function>
2997 <function id="ForceEarlyReturnLong" num="83" since="1.1">
2998 <synopsis>Force Early Return - Long</synopsis>
2999 <description>
3000 This function can be used to return from a method whose
3001 result type is <code>long</code>.
3002 </description>
3003 <origin>new</origin>
3004 <capabilities>
3005 <required id="can_force_early_return"></required>
3006 </capabilities>
3007 <parameters>
3008 <param id="thread">
3009 <jthread null="current"/>
3010 <description>
3011 The thread whose current frame is to return early.
3012 </description>
3013 </param>
3014 <param id="value">
3015 <jlong/>
3016 <description>
3017 The return value for the called frame.
3018 </description>
3019 </param>
3020 </parameters>
3021 <errors>
3022 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3023 Attempted to return early from a frame
3024 corresponding to a native method.
3025 Or the implementation is unable to provide
3026 this functionality on this frame.
3027 </error>
3028 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3029 The result type of the called method is not <code>long</code>.
3030 </error>
3031 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3032 Thread was not the current thread and was not suspended.
3033 </error>
3034 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3035 There are no frames on the call stack.
3036 </error>
3037 </errors>
3038 </function>
3040 <function id="ForceEarlyReturnFloat" num="84" since="1.1">
3041 <synopsis>Force Early Return - Float</synopsis>
3042 <description>
3043 This function can be used to return from a method whose
3044 result type is <code>float</code>.
3045 </description>
3046 <origin>new</origin>
3047 <capabilities>
3048 <required id="can_force_early_return"></required>
3049 </capabilities>
3050 <parameters>
3051 <param id="thread">
3052 <jthread null="current"/>
3053 <description>
3054 The thread whose current frame is to return early.
3055 </description>
3056 </param>
3057 <param id="value">
3058 <jfloat/>
3059 <description>
3060 The return value for the called frame.
3061 </description>
3062 </param>
3063 </parameters>
3064 <errors>
3065 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3066 Attempted to return early from a frame
3067 corresponding to a native method.
3068 Or the implementation is unable to provide
3069 this functionality on this frame.
3070 </error>
3071 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3072 The result type of the called method is not <code>float</code>.
3073 </error>
3074 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3075 Thread was not the current thread and was not suspended.
3076 </error>
3077 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3078 There are no frames on the call stack.
3079 </error>
3080 </errors>
3081 </function>
3083 <function id="ForceEarlyReturnDouble" num="85" since="1.1">
3084 <synopsis>Force Early Return - Double</synopsis>
3085 <description>
3086 This function can be used to return from a method whose
3087 result type is <code>double</code>.
3088 </description>
3089 <origin>new</origin>
3090 <capabilities>
3091 <required id="can_force_early_return"></required>
3092 </capabilities>
3093 <parameters>
3094 <param id="thread">
3095 <jthread null="current"/>
3096 <description>
3097 The thread whose current frame is to return early.
3098 </description>
3099 </param>
3100 <param id="value">
3101 <jdouble/>
3102 <description>
3103 The return value for the called frame.
3104 </description>
3105 </param>
3106 </parameters>
3107 <errors>
3108 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3109 Attempted to return early from a frame corresponding to a native method.
3110 Or the implementation is unable to provide this functionality on this frame.
3111 </error>
3112 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3113 The result type of the called method is not <code>double</code>.
3114 </error>
3115 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3116 Thread was not the current thread and was not suspended.
3117 </error>
3118 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3119 There are no frames on the call stack.
3120 </error>
3121 </errors>
3122 </function>
3124 <function id="ForceEarlyReturnVoid" num="86" since="1.1">
3125 <synopsis>Force Early Return - Void</synopsis>
3126 <description>
3127 This function can be used to return from a method with no result type.
3128 That is, the called method must be declared <code>void</code>.
3129 </description>
3130 <origin>new</origin>
3131 <capabilities>
3132 <required id="can_force_early_return"></required>
3133 </capabilities>
3134 <parameters>
3135 <param id="thread">
3136 <jthread null="current"/>
3137 <description>
3138 The thread whose current frame is to return early.
3139 </description>
3140 </param>
3141 </parameters>
3142 <errors>
3143 <error id="JVMTI_ERROR_OPAQUE_FRAME">
3144 Attempted to return early from a frame
3145 corresponding to a native method.
3146 Or the implementation is unable to provide
3147 this functionality on this frame.
3148 </error>
3149 <error id="JVMTI_ERROR_TYPE_MISMATCH">
3150 The called method has a result type.
3151 </error>
3152 <error id="JVMTI_ERROR_THREAD_NOT_SUSPENDED">
3153 Thread was not the current thread and was not suspended.
3154 </error>
3155 <error id="JVMTI_ERROR_NO_MORE_FRAMES">
3156 There are no frames on the call stack.
3157 </error>
3158 </errors>
3159 </function>
3161 </category>
3163 <category id="Heap" label="Heap">
3164 <intro>
3165 These functions are used to analyze the heap.
3166 Functionality includes the ability to view the objects in the
3167 heap and to tag these objects.
3168 </intro>
3170 <intro id="objectTags" label="Object Tags">
3171 A <i>tag</i> is a value associated with an object.
3172 Tags are explicitly set by the agent using the
3173 <functionlink id="SetTag"></functionlink> function or by
3174 callback functions such as <functionlink id="jvmtiHeapIterationCallback"/>.
3175 <p/>
3176 Tags are local to the environment; that is, the tags of one
3177 environment are not visible in another.
3178 <p/>
3179 Tags are <code>jlong</code> values which can be used
3180 simply to mark an object or to store a pointer to more detailed
3181 information. Objects which have not been tagged have a
3182 tag of zero.
3183 Setting a tag to zero makes the object untagged.
3184 </intro>
3186 <intro id="heapCallbacks" label="Heap Callback Functions">
3187 Heap functions which iterate through the heap and recursively
3188 follow object references use agent supplied callback functions
3189 to deliver the information.
3190 <p/>
3191 These heap callback functions must adhere to the following restrictions --
3192 These callbacks must not use JNI functions.
3193 These callbacks must not use <jvmti/> functions except
3194 <i>callback safe</i> functions which
3195 specifically allow such use (see the raw monitor, memory management,
3196 and environment local storage functions).
3197 <p/>
3198 An implementation may invoke a callback on an internal thread or
3199 the thread which called the iteration function.
3200 Heap callbacks are single threaded -- no more than one callback will
3201 be invoked at a time.
3202 <p/>
3203 The Heap Filter Flags can be used to prevent reporting
3204 based on the tag status of an object or its class.
3205 If no flags are set (the <code>jint</code> is zero), objects
3206 will not be filtered out.
3208 <constants id="jvmtiHeapFilter" label="Heap Filter Flags" kind="bits">
3209 <constant id="JVMTI_HEAP_FILTER_TAGGED" num="0x4">
3210 Filter out tagged objects. Objects which are tagged are not included.
3211 </constant>
3212 <constant id="JVMTI_HEAP_FILTER_UNTAGGED" num="0x8">
3213 Filter out untagged objects. Objects which are not tagged are not included.
3214 </constant>
3215 <constant id="JVMTI_HEAP_FILTER_CLASS_TAGGED" num="0x10">
3216 Filter out objects with tagged classes. Objects whose class is tagged are not included.
3217 </constant>
3218 <constant id="JVMTI_HEAP_FILTER_CLASS_UNTAGGED" num="0x20">
3219 Filter out objects with untagged classes. Objects whose class is not tagged are not included.
3220 </constant>
3221 </constants>
3223 <p/>
3224 The Heap Visit Control Flags are returned by the heap callbacks
3225 and can be used to abort the iteration. For the
3226 <functionlink id="jvmtiHeapReferenceCallback">Heap
3227 Reference Callback</functionlink>, it can also be used
3228 to prune the graph of traversed references
3229 (<code>JVMTI_VISIT_OBJECTS</code> is not set).
3231 <constants id="jvmtiHeapVisitControl"
3232 label="Heap Visit Control Flags"
3233 kind="bits"
3234 since="1.1">
3235 <constant id="JVMTI_VISIT_OBJECTS" num="0x100">
3236 If we are visiting an object and if this callback
3237 was initiated by <functionlink id="FollowReferences"/>,
3238 traverse the references of this object.
3239 Otherwise ignored.
3240 </constant>
3241 <constant id="JVMTI_VISIT_ABORT" num="0x8000">
3242 Abort the iteration. Ignore all other bits.
3243 </constant>
3244 </constants>
3246 <p/>
3247 The Heap Reference Enumeration is provided by the
3248 <functionlink id="jvmtiHeapReferenceCallback">Heap
3249 Reference Callback</functionlink> and
3250 <functionlink id="jvmtiPrimitiveFieldCallback">Primitive Field
3251 Callback</functionlink> to
3252 describe the kind of reference
3253 being reported.
3255 <constants id="jvmtiHeapReferenceKind"
3256 label="Heap Reference Enumeration"
3257 kind="enum"
3258 since="1.1">
3259 <constant id="JVMTI_HEAP_REFERENCE_CLASS" num="1">
3260 Reference from an object to its class.
3261 </constant>
3262 <constant id="JVMTI_HEAP_REFERENCE_FIELD" num="2">
3263 Reference from an object to the value of one of its instance fields.
3264 </constant>
3265 <constant id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT" num="3">
3266 Reference from an array to one of its elements.
3267 </constant>
3268 <constant id="JVMTI_HEAP_REFERENCE_CLASS_LOADER" num="4">
3269 Reference from a class to its class loader.
3270 </constant>
3271 <constant id="JVMTI_HEAP_REFERENCE_SIGNERS" num="5">
3272 Reference from a class to its signers array.
3273 </constant>
3274 <constant id="JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN" num="6">
3275 Reference from a class to its protection domain.
3276 </constant>
3277 <constant id="JVMTI_HEAP_REFERENCE_INTERFACE" num="7">
3278 Reference from a class to one of its interfaces.
3279 Note: interfaces are defined via a constant pool reference,
3280 so the referenced interfaces may also be reported with a
3281 <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3282 </constant>
3283 <constant id="JVMTI_HEAP_REFERENCE_STATIC_FIELD" num="8">
3284 Reference from a class to the value of one of its static fields.
3285 </constant>
3286 <constant id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL" num="9">
3287 Reference from a class to a resolved entry in the constant pool.
3288 </constant>
3289 <constant id="JVMTI_HEAP_REFERENCE_SUPERCLASS" num="10">
3290 Reference from a class to its superclass.
3291 A callback is bot sent if the superclass is <code>java.lang.Object</code>.
3292 Note: loaded classes define superclasses via a constant pool
3293 reference, so the referenced superclass may also be reported with
3294 a <code>JVMTI_HEAP_REFERENCE_CONSTANT_POOL</code> reference kind.
3295 </constant>
3296 <constant id="JVMTI_HEAP_REFERENCE_JNI_GLOBAL" num="21">
3297 Heap root reference: JNI global reference.
3298 </constant>
3299 <constant id="JVMTI_HEAP_REFERENCE_SYSTEM_CLASS" num="22">
3300 Heap root reference: System class.
3301 </constant>
3302 <constant id="JVMTI_HEAP_REFERENCE_MONITOR" num="23">
3303 Heap root reference: monitor.
3304 </constant>
3305 <constant id="JVMTI_HEAP_REFERENCE_STACK_LOCAL" num="24">
3306 Heap root reference: local variable on the stack.
3307 </constant>
3308 <constant id="JVMTI_HEAP_REFERENCE_JNI_LOCAL" num="25">
3309 Heap root reference: JNI local reference.
3310 </constant>
3311 <constant id="JVMTI_HEAP_REFERENCE_THREAD" num="26">
3312 Heap root reference: Thread.
3313 </constant>
3314 <constant id="JVMTI_HEAP_REFERENCE_OTHER" num="27">
3315 Heap root reference: other heap root reference.
3316 </constant>
3317 </constants>
3319 <p/>
3320 Definitions for the single character type descriptors of
3321 primitive types.
3323 <constants id="jvmtiPrimitiveType"
3324 label="Primitive Type Enumeration"
3325 kind="enum"
3326 since="1.1">
3327 <constant id="JVMTI_PRIMITIVE_TYPE_BOOLEAN" num="90">
3328 'Z' - Java programming language <code>boolean</code> - JNI <code>jboolean</code>
3329 </constant>
3330 <constant id="JVMTI_PRIMITIVE_TYPE_BYTE" num="66">
3331 'B' - Java programming language <code>byte</code> - JNI <code>jbyte</code>
3332 </constant>
3333 <constant id="JVMTI_PRIMITIVE_TYPE_CHAR" num="67">
3334 'C' - Java programming language <code>char</code> - JNI <code>jchar</code>
3335 </constant>
3336 <constant id="JVMTI_PRIMITIVE_TYPE_SHORT" num="83">
3337 'S' - Java programming language <code>short</code> - JNI <code>jshort</code>
3338 </constant>
3339 <constant id="JVMTI_PRIMITIVE_TYPE_INT" num="73">
3340 'I' - Java programming language <code>int</code> - JNI <code>jint</code>
3341 </constant>
3342 <constant id="JVMTI_PRIMITIVE_TYPE_LONG" num="74">
3343 'J' - Java programming language <code>long</code> - JNI <code>jlong</code>
3344 </constant>
3345 <constant id="JVMTI_PRIMITIVE_TYPE_FLOAT" num="70">
3346 'F' - Java programming language <code>float</code> - JNI <code>jfloat</code>
3347 </constant>
3348 <constant id="JVMTI_PRIMITIVE_TYPE_DOUBLE" num="68">
3349 'D' - Java programming language <code>double</code> - JNI <code>jdouble</code>
3350 </constant>
3351 </constants>
3352 </intro>
3354 <typedef id="jvmtiHeapReferenceInfoField"
3355 label="Reference information structure for Field references"
3356 since="1.1">
3357 <description>
3358 Reference information returned for
3359 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> and
3360 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3361 </description>
3362 <field id="index">
3363 <jint/>
3364 <description>
3365 For <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>, the
3366 referrer object is not a class or an inteface.
3367 In this case, <code>index</code> is the index of the field
3368 in the class of the referrer object.
3369 This class is referred to below as <i>C</i>.
3370 <p/>
3371 For <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
3372 the referrer object is a class (referred to below as <i>C</i>)
3373 or an interface (referred to below as <i>I</i>).
3374 In this case, <code>index</code> is the index of the field in
3375 that class or interface.
3376 <p/>
3377 If the referrer object is not an interface, then the field
3378 indices are determined as follows:
3379 <ul>
3380 <li>make a list of all the fields in <i>C</i> and its
3381 superclasses, starting with all the fields in
3382 <code>java.lang.Object</code> and ending with all the
3383 fields in <i>C</i>.</li>
3384 <li>Within this list, put
3385 the fields for a given class in the order returned by
3386 <functionlink id="GetClassFields"/>.</li>
3387 <li>Assign the fields in this list indices
3388 <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3389 is the count of the fields in all the interfaces
3390 implemented by <i>C</i>.
3391 Note that <i>C</i> implements all interfaces
3392 directly implemented by its superclasses; as well
3393 as all superinterfaces of these interfaces.</li>
3394 </ul>
3395 If the referrer object is an interface, then the field
3396 indices are determined as follows:
3397 <ul>
3398 <li>make a list of the fields directly declared in
3399 <i>I</i>.</li>
3400 <li>Within this list, put
3401 the fields in the order returned by
3402 <functionlink id="GetClassFields"/>.</li>
3403 <li>Assign the fields in this list indices
3404 <i>n</i>, <i>n</i>+1, ..., in order, where <i>n</i>
3405 is the count of the fields in all the superinterfaces
3406 of <i>I</i>.</li>
3407 </ul>
3408 All fields are included in this computation, regardless of
3409 field modifier (static, public, private, etc).
3410 <p/>
3411 For example, given the following classes and interfaces:
3412 <example>
3413 interface I0 {
3414 int p = 0;
3415 }
3417 interface I1 extends I0 {
3418 int x = 1;
3419 }
3421 interface I2 extends I0 {
3422 int y = 2;
3423 }
3425 class C1 implements I1 {
3426 public static int a = 3;
3427 private int b = 4;
3428 }
3430 class C2 extends C1 implements I2 {
3431 static int q = 5;
3432 final int r = 6;
3433 }
3434 </example>
3435 Assume that <functionlink id="GetClassFields"/> called on
3436 <code>C1</code> returns the fields of <code>C1</code> in the
3437 order: a, b; and that the fields of <code>C2</code> are
3438 returned in the order: q, r.
3439 An instance of class <code>C1</code> will have the
3440 following field indices:
3441 <dl><dd><table>
3442 <tr>
3443 <td>
3444 a
3445 </td>
3446 <td>
3447 2
3448 </td>
3449 <td align="left">
3450 The count of the fields in the interfaces
3451 implemented by <code>C1</code> is two (<i>n</i>=2):
3452 <code>p</code> of <code>I0</code>
3453 and <code>x</code> of <code>I1</code>.
3454 </td>
3455 </tr>
3456 <tr>
3457 <td>
3458 b
3459 </td>
3460 <td>
3461 3
3462 </td>
3463 <td align="left">
3464 the subsequent index.
3465 </td>
3466 </tr>
3467 </table></dd></dl>
3468 The class <code>C1</code> will have the same field indices.
3469 <p/>
3470 An instance of class <code>C2</code> will have the
3471 following field indices:
3472 <dl><dd><table>
3473 <tr>
3474 <td>
3475 a
3476 </td>
3477 <td>
3478 3
3479 </td>
3480 <td align="left">
3481 The count of the fields in the interfaces
3482 implemented by <code>C2</code> is three (<i>n</i>=3):
3483 <code>p</code> of <code>I0</code>,
3484 <code>x</code> of <code>I1</code> and <code>y</code> of <code>I2</code>
3485 (an interface of <code>C2</code>). Note that the field <code>p</code>
3486 of <code>I0</code> is only included once.
3487 </td>
3488 </tr>
3489 <tr>
3490 <td>
3491 b
3492 </td>
3493 <td>
3494 4
3495 </td>
3496 <td align="left">
3497 the subsequent index to "a".
3498 </td>
3499 </tr>
3500 <tr>
3501 <td>
3502 q
3503 </td>
3504 <td>
3505 5
3506 </td>
3507 <td align="left">
3508 the subsequent index to "b".
3509 </td>
3510 </tr>
3511 <tr>
3512 <td>
3513 r
3514 </td>
3515 <td>
3516 6
3517 </td>
3518 <td align="left">
3519 the subsequent index to "q".
3520 </td>
3521 </tr>
3522 </table></dd></dl>
3523 The class <code>C2</code> will have the same field indices.
3524 Note that a field may have a different index depending on the
3525 object that is viewing it -- for example field "a" above.
3526 Note also: not all field indices may be visible from the
3527 callbacks, but all indices are shown for illustrative purposes.
3528 <p/>
3529 The interface <code>I1</code> will have the
3530 following field indices:
3531 <dl><dd><table>
3532 <tr>
3533 <td>
3534 x
3535 </td>
3536 <td>
3537 1
3538 </td>
3539 <td align="left">
3540 The count of the fields in the superinterfaces
3541 of <code>I1</code> is one (<i>n</i>=1):
3542 <code>p</code> of <code>I0</code>.
3543 </td>
3544 </tr>
3545 </table></dd></dl>
3546 </description>
3547 </field>
3548 </typedef>
3550 <typedef id="jvmtiHeapReferenceInfoArray"
3551 label="Reference information structure for Array references"
3552 since="1.1">
3553 <description>
3554 Reference information returned for
3555 <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3556 </description>
3557 <field id="index">
3558 <jint/>
3559 <description>
3560 The array index.
3561 </description>
3562 </field>
3563 </typedef>
3565 <typedef id="jvmtiHeapReferenceInfoConstantPool"
3566 label="Reference information structure for Constant Pool references"
3567 since="1.1">
3568 <description>
3569 Reference information returned for
3570 <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3571 </description>
3572 <field id="index">
3573 <jint/>
3574 <description>
3575 The index into the constant pool of the class. See the description in
3576 <vmspec chapter="4.4"/>.
3577 </description>
3578 </field>
3579 </typedef>
3581 <typedef id="jvmtiHeapReferenceInfoStackLocal"
3582 label="Reference information structure for Local Variable references"
3583 since="1.1">
3584 <description>
3585 Reference information returned for
3586 <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3587 </description>
3588 <field id="thread_tag">
3589 <jlong/>
3590 <description>
3591 The tag of the thread corresponding to this stack, zero if not tagged.
3592 </description>
3593 </field>
3594 <field id="thread_id">
3595 <jlong/>
3596 <description>
3597 The unique thread ID of the thread corresponding to this stack.
3598 </description>
3599 </field>
3600 <field id="depth">
3601 <jint/>
3602 <description>
3603 The depth of the frame.
3604 </description>
3605 </field>
3606 <field id="method">
3607 <jmethodID/>
3608 <description>
3609 The method executing in this frame.
3610 </description>
3611 </field>
3612 <field id="location">
3613 <jlocation/>
3614 <description>
3615 The currently executing location in this frame.
3616 </description>
3617 </field>
3618 <field id="slot">
3619 <jint/>
3620 <description>
3621 The slot number of the local variable.
3622 </description>
3623 </field>
3624 </typedef>
3626 <typedef id="jvmtiHeapReferenceInfoJniLocal"
3627 label="Reference information structure for JNI local references"
3628 since="1.1">
3629 <description>
3630 Reference information returned for
3631 <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3632 </description>
3633 <field id="thread_tag">
3634 <jlong/>
3635 <description>
3636 The tag of the thread corresponding to this stack, zero if not tagged.
3637 </description>
3638 </field>
3639 <field id="thread_id">
3640 <jlong/>
3641 <description>
3642 The unique thread ID of the thread corresponding to this stack.
3643 </description>
3644 </field>
3645 <field id="depth">
3646 <jint/>
3647 <description>
3648 The depth of the frame.
3649 </description>
3650 </field>
3651 <field id="method">
3652 <jmethodID/>
3653 <description>
3654 The method executing in this frame.
3655 </description>
3656 </field>
3657 </typedef>
3659 <typedef id="jvmtiHeapReferenceInfoReserved"
3660 label="Reference information structure for Other references"
3661 since="1.1">
3662 <description>
3663 Reference information returned for other references.
3664 </description>
3665 <field id="reserved1">
3666 <jlong/>
3667 <description>
3668 reserved for future use.
3669 </description>
3670 </field>
3671 <field id="reserved2">
3672 <jlong/>
3673 <description>
3674 reserved for future use.
3675 </description>
3676 </field>
3677 <field id="reserved3">
3678 <jlong/>
3679 <description>
3680 reserved for future use.
3681 </description>
3682 </field>
3683 <field id="reserved4">
3684 <jlong/>
3685 <description>
3686 reserved for future use.
3687 </description>
3688 </field>
3689 <field id="reserved5">
3690 <jlong/>
3691 <description>
3692 reserved for future use.
3693 </description>
3694 </field>
3695 <field id="reserved6">
3696 <jlong/>
3697 <description>
3698 reserved for future use.
3699 </description>
3700 </field>
3701 <field id="reserved7">
3702 <jlong/>
3703 <description>
3704 reserved for future use.
3705 </description>
3706 </field>
3707 <field id="reserved8">
3708 <jlong/>
3709 <description>
3710 reserved for future use.
3711 </description>
3712 </field>
3713 </typedef>
3715 <uniontypedef id="jvmtiHeapReferenceInfo"
3716 label="Reference information structure"
3717 since="1.1">
3718 <description>
3719 The information returned about referrers.
3720 Represented as a union of the various kinds of reference information.
3721 </description>
3722 <field id="field">
3723 <struct>jvmtiHeapReferenceInfoField</struct>
3724 <description>
3725 The referrer information for
3726 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>
3727 and <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/> references.
3728 </description>
3729 </field>
3730 <field id="array">
3731 <struct>jvmtiHeapReferenceInfoArray</struct>
3732 <description>
3733 The referrer information for
3734 For <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/> references.
3735 </description>
3736 </field>
3737 <field id="constant_pool">
3738 <struct>jvmtiHeapReferenceInfoConstantPool</struct>
3739 <description>
3740 The referrer information for
3741 For <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/> references.
3742 </description>
3743 </field>
3744 <field id="stack_local">
3745 <struct>jvmtiHeapReferenceInfoStackLocal</struct>
3746 <description>
3747 The referrer information for
3748 For <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/> references.
3749 </description>
3750 </field>
3751 <field id="jni_local">
3752 <struct>jvmtiHeapReferenceInfoJniLocal</struct>
3753 <description>
3754 The referrer information for
3755 For <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/> references.
3756 </description>
3757 </field>
3758 <field id="other">
3759 <struct>jvmtiHeapReferenceInfoReserved</struct>
3760 <description>
3761 reserved for future use.
3762 </description>
3763 </field>
3764 </uniontypedef>
3766 <typedef id="jvmtiHeapCallbacks"
3767 label="Heap callback function structure"
3768 since="1.1">
3769 <field id="heap_iteration_callback">
3770 <ptrtype>
3771 <struct>jvmtiHeapIterationCallback</struct>
3772 </ptrtype>
3773 <description>
3774 The callback to be called to describe an
3775 object in the heap. Used by the
3776 <functionlink id="IterateThroughHeap"/> function, ignored by the
3777 <functionlink id="FollowReferences"/> function.
3778 </description>
3779 </field>
3780 <field id="heap_reference_callback">
3781 <ptrtype>
3782 <struct>jvmtiHeapReferenceCallback</struct>
3783 </ptrtype>
3784 <description>
3785 The callback to be called to describe an
3786 object reference. Used by the
3787 <functionlink id="FollowReferences"/> function, ignored by the
3788 <functionlink id="IterateThroughHeap"/> function.
3789 </description>
3790 </field>
3791 <field id="primitive_field_callback">
3792 <ptrtype>
3793 <struct>jvmtiPrimitiveFieldCallback</struct>
3794 </ptrtype>
3795 <description>
3796 The callback to be called to describe a
3797 primitive field.
3798 </description>
3799 </field>
3800 <field id="array_primitive_value_callback">
3801 <ptrtype>
3802 <struct>jvmtiArrayPrimitiveValueCallback</struct>
3803 </ptrtype>
3804 <description>
3805 The callback to be called to describe an
3806 array of primitive values.
3807 </description>
3808 </field>
3809 <field id="string_primitive_value_callback">
3810 <ptrtype>
3811 <struct>jvmtiStringPrimitiveValueCallback</struct>
3812 </ptrtype>
3813 <description>
3814 The callback to be called to describe a String value.
3815 </description>
3816 </field>
3817 <field id="reserved5">
3818 <ptrtype>
3819 <struct>jvmtiReservedCallback</struct>
3820 </ptrtype>
3821 <description>
3822 Reserved for future use..
3823 </description>
3824 </field>
3825 <field id="reserved6">
3826 <ptrtype>
3827 <struct>jvmtiReservedCallback</struct>
3828 </ptrtype>
3829 <description>
3830 Reserved for future use..
3831 </description>
3832 </field>
3833 <field id="reserved7">
3834 <ptrtype>
3835 <struct>jvmtiReservedCallback</struct>
3836 </ptrtype>
3837 <description>
3838 Reserved for future use..
3839 </description>
3840 </field>
3841 <field id="reserved8">
3842 <ptrtype>
3843 <struct>jvmtiReservedCallback</struct>
3844 </ptrtype>
3845 <description>
3846 Reserved for future use..
3847 </description>
3848 </field>
3849 <field id="reserved9">
3850 <ptrtype>
3851 <struct>jvmtiReservedCallback</struct>
3852 </ptrtype>
3853 <description>
3854 Reserved for future use..
3855 </description>
3856 </field>
3857 <field id="reserved10">
3858 <ptrtype>
3859 <struct>jvmtiReservedCallback</struct>
3860 </ptrtype>
3861 <description>
3862 Reserved for future use..
3863 </description>
3864 </field>
3865 <field id="reserved11">
3866 <ptrtype>
3867 <struct>jvmtiReservedCallback</struct>
3868 </ptrtype>
3869 <description>
3870 Reserved for future use..
3871 </description>
3872 </field>
3873 <field id="reserved12">
3874 <ptrtype>
3875 <struct>jvmtiReservedCallback</struct>
3876 </ptrtype>
3877 <description>
3878 Reserved for future use..
3879 </description>
3880 </field>
3881 <field id="reserved13">
3882 <ptrtype>
3883 <struct>jvmtiReservedCallback</struct>
3884 </ptrtype>
3885 <description>
3886 Reserved for future use..
3887 </description>
3888 </field>
3889 <field id="reserved14">
3890 <ptrtype>
3891 <struct>jvmtiReservedCallback</struct>
3892 </ptrtype>
3893 <description>
3894 Reserved for future use..
3895 </description>
3896 </field>
3897 <field id="reserved15">
3898 <ptrtype>
3899 <struct>jvmtiReservedCallback</struct>
3900 </ptrtype>
3901 <description>
3902 Reserved for future use..
3903 </description>
3904 </field>
3905 </typedef>
3908 <intro>
3909 <rationale>
3910 The heap dumping functionality (below) uses a callback
3911 for each object. While it would seem that a buffered approach
3912 would provide better throughput, tests do
3913 not show this to be the case--possibly due to locality of
3914 memory reference or array access overhead.
3915 </rationale>
3917 <issue>
3918 Still under investigation as to if java.lang.ref references
3919 are reported as a different type of reference.
3920 </issue>
3922 <issue>
3923 Should or can an indication of the cost or relative cost of
3924 these operations be included?
3925 </issue>
3927 </intro>
3929 <callback id="jvmtiHeapIterationCallback" since="1.1">
3930 <jint/>
3931 <synopsis>Heap Iteration Callback</synopsis>
3932 <description>
3933 Agent supplied callback function.
3934 Describes (but does not pass in) an object in the heap.
3935 <p/>
3936 This function should return a bit vector of the desired
3937 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
3938 This will determine if the entire iteration should be aborted
3939 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
3940 <p/>
3941 See the <internallink id="heapCallbacks">heap callback
3942 function restrictions</internallink>.
3943 </description>
3944 <parameters>
3945 <param id="class_tag">
3946 <jlong/>
3947 <description>
3948 The tag of the class of object (zero if the class is not tagged).
3949 If the object represents a runtime class,
3950 the <code>class_tag</code> is the tag
3951 associated with <code>java.lang.Class</code>
3952 (zero if <code>java.lang.Class</code> is not tagged).
3953 </description>
3954 </param>
3955 <param id="size">
3956 <jlong/>
3957 <description>
3958 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
3959 </description>
3960 </param>
3961 <param id="tag_ptr">
3962 <outptr><jlong/></outptr>
3963 <description>
3964 The object tag value, or zero if the object is not tagged.
3965 To set the tag value to be associated with the object
3966 the agent sets the <code>jlong</code> pointed to by the parameter.
3967 </description>
3968 </param>
3969 <param id="length">
3970 <jint/>
3971 <description>
3972 If this object is an array, the length of the array. Otherwise negative one (-1).
3973 </description>
3974 </param>
3975 <param id="user_data">
3976 <outptr><void/></outptr>
3977 <description>
3978 The user supplied data that was passed into the iteration function.
3979 </description>
3980 </param>
3981 </parameters>
3982 </callback>
3984 <callback id="jvmtiHeapReferenceCallback" since="1.1">
3985 <jint/>
3986 <synopsis>Heap Reference Callback</synopsis>
3987 <description>
3988 Agent supplied callback function.
3989 Describes a reference from an object or the VM (the referrer) to another object
3990 (the referree) or a heap root to a referree.
3991 <p/>
3992 This function should return a bit vector of the desired
3993 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
3994 This will determine if the objects referenced by the referree
3995 should be visited or if the entire iteration should be aborted.
3996 <p/>
3997 See the <internallink id="heapCallbacks">heap callback
3998 function restrictions</internallink>.
3999 </description>
4000 <parameters>
4001 <param id="reference_kind">
4002 <enum>jvmtiHeapReferenceKind</enum>
4003 <description>
4004 The kind of reference.
4005 </description>
4006 </param>
4007 <param id="reference_info">
4008 <inptr>
4009 <struct>jvmtiHeapReferenceInfo</struct>
4010 </inptr>
4011 <description>
4012 Details about the reference.
4013 Set when the <paramlink id="reference_kind"/> is
4014 <datalink id="JVMTI_HEAP_REFERENCE_FIELD"/>,
4015 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>,
4016 <datalink id="JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT"/>,
4017 <datalink id="JVMTI_HEAP_REFERENCE_CONSTANT_POOL"/>,
4018 <datalink id="JVMTI_HEAP_REFERENCE_STACK_LOCAL"/>,
4019 or <datalink id="JVMTI_HEAP_REFERENCE_JNI_LOCAL"/>.
4020 Otherwise <code>NULL</code>.
4021 </description>
4022 </param>
4023 <param id="class_tag">
4024 <jlong/>
4025 <description>
4026 The tag of the class of referree object (zero if the class is not tagged).
4027 If the referree object represents a runtime class,
4028 the <code>class_tag</code> is the tag
4029 associated with <code>java.lang.Class</code>
4030 (zero if <code>java.lang.Class</code> is not tagged).
4031 </description>
4032 </param>
4033 <param id="referrer_class_tag">
4034 <jlong/>
4035 <description>
4036 The tag of the class of the referrer object (zero if the class is not tagged
4037 or the referree is a heap root). If the referrer object represents a runtime
4038 class, the <code>referrer_class_tag</code> is the tag associated with
4039 the <code>java.lang.Class</code>
4040 (zero if <code>java.lang.Class</code> is not tagged).
4041 </description>
4042 </param>
4043 <param id="size">
4044 <jlong/>
4045 <description>
4046 Size of the referree object (in bytes).
4047 See <functionlink id="GetObjectSize"/>.
4048 </description>
4049 </param>
4050 <param id="tag_ptr">
4051 <outptr><jlong/></outptr>
4052 <description>
4053 Points to the referree object tag value, or zero if the object is not
4054 tagged.
4055 To set the tag value to be associated with the object
4056 the agent sets the <code>jlong</code> pointed to by the parameter.
4057 </description>
4058 </param>
4059 <param id="referrer_tag_ptr">
4060 <outptr><jlong/></outptr>
4061 <description>
4062 Points to the tag of the referrer object, or
4063 points to the zero if the referrer
4064 object is not tagged.
4065 <code>NULL</code> if the referrer in not an object (that is,
4066 this callback is reporting a heap root).
4067 To set the tag value to be associated with the referrer object
4068 the agent sets the <code>jlong</code> pointed to by the parameter.
4069 If this callback is reporting a reference from an object to itself,
4070 <code>referrer_tag_ptr == tag_ptr</code>.
4071 </description>
4072 </param>
4073 <param id="length">
4074 <jint/>
4075 <description>
4076 If this object is an array, the length of the array. Otherwise negative one (-1).
4077 </description>
4078 </param>
4079 <param id="user_data">
4080 <outptr><void/></outptr>
4081 <description>
4082 The user supplied data that was passed into the iteration function.
4083 </description>
4084 </param>
4085 </parameters>
4086 </callback>
4088 <callback id="jvmtiPrimitiveFieldCallback" since="1.1">
4089 <jint/>
4090 <synopsis>Primitive Field Callback</synopsis>
4091 <description>
4092 Agent supplied callback function which
4093 describes a primitive field of an object (<i>the object</i>).
4094 A primitive field is a field whose type is a primitive type.
4095 This callback will describe a static field if the object is a class,
4096 and otherwise will describe an instance field.
4097 <p/>
4098 This function should return a bit vector of the desired
4099 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4100 This will determine if the entire iteration should be aborted
4101 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4102 <p/>
4103 See the <internallink id="heapCallbacks">heap callback
4104 function restrictions</internallink>.
4105 </description>
4106 <parameters>
4107 <param id="kind">
4108 <enum>jvmtiHeapReferenceKind</enum>
4109 <description>
4110 The kind of field -- instance or static (<datalink id="JVMTI_HEAP_REFERENCE_FIELD"/> or
4111 <datalink id="JVMTI_HEAP_REFERENCE_STATIC_FIELD"/>).
4112 </description>
4113 </param>
4114 <param id="info">
4115 <inptr>
4116 <struct>jvmtiHeapReferenceInfo</struct>
4117 </inptr>
4118 <description>
4119 Which field (the field index).
4120 </description>
4121 </param>
4122 <param id="object_class_tag">
4123 <jlong/>
4124 <description>
4125 The tag of the class of the object (zero if the class is not tagged).
4126 If the object represents a runtime class, the
4127 <code>object_class_tag</code> is the tag
4128 associated with <code>java.lang.Class</code>
4129 (zero if <code>java.lang.Class</code> is not tagged).
4130 </description>
4131 </param>
4132 <param id="object_tag_ptr">
4133 <outptr><jlong/></outptr>
4134 <description>
4135 Points to the tag of the object, or zero if the object is not
4136 tagged.
4137 To set the tag value to be associated with the object
4138 the agent sets the <code>jlong</code> pointed to by the parameter.
4139 </description>
4140 </param>
4141 <param id="value">
4142 <jvalue/>
4143 <description>
4144 The value of the field.
4145 </description>
4146 </param>
4147 <param id="value_type">
4148 <enum>jvmtiPrimitiveType</enum>
4149 <description>
4150 The type of the field.
4151 </description>
4152 </param>
4153 <param id="user_data">
4154 <outptr><void/></outptr>
4155 <description>
4156 The user supplied data that was passed into the iteration function.
4157 </description>
4158 </param>
4159 </parameters>
4160 </callback>
4162 <callback id="jvmtiArrayPrimitiveValueCallback" since="1.1">
4163 <jint/>
4164 <synopsis>Array Primitive Value Callback</synopsis>
4165 <description>
4166 Agent supplied callback function.
4167 Describes the values in an array of a primitive type.
4168 <p/>
4169 This function should return a bit vector of the desired
4170 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4171 This will determine if the entire iteration should be aborted
4172 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4173 <p/>
4174 See the <internallink id="heapCallbacks">heap callback
4175 function restrictions</internallink>.
4176 </description>
4177 <parameters>
4178 <param id="class_tag">
4179 <jlong/>
4180 <description>
4181 The tag of the class of the array object (zero if the class is not tagged).
4182 </description>
4183 </param>
4184 <param id="size">
4185 <jlong/>
4186 <description>
4187 Size of the array (in bytes).
4188 See <functionlink id="GetObjectSize"/>.
4189 </description>
4190 </param>
4191 <param id="tag_ptr">
4192 <outptr><jlong/></outptr>
4193 <description>
4194 Points to the tag of the array object, or zero if the object is not
4195 tagged.
4196 To set the tag value to be associated with the object
4197 the agent sets the <code>jlong</code> pointed to by the parameter.
4198 </description>
4199 </param>
4200 <param id="element_count">
4201 <jint/>
4202 <description>
4203 The length of the primitive array.
4204 </description>
4205 </param>
4206 <param id="element_type">
4207 <enum>jvmtiPrimitiveType</enum>
4208 <description>
4209 The type of the elements of the array.
4210 </description>
4211 </param>
4212 <param id="elements">
4213 <vmbuf><void/></vmbuf>
4214 <description>
4215 The elements of the array in a packed array of <code>element_count</code>
4216 items of <code>element_type</code> size each.
4217 </description>
4218 </param>
4219 <param id="user_data">
4220 <outptr><void/></outptr>
4221 <description>
4222 The user supplied data that was passed into the iteration function.
4223 </description>
4224 </param>
4225 </parameters>
4226 </callback>
4228 <callback id="jvmtiStringPrimitiveValueCallback" since="1.1">
4229 <jint/>
4230 <synopsis>String Primitive Value Callback</synopsis>
4231 <description>
4232 Agent supplied callback function.
4233 Describes the value of a java.lang.String.
4234 <p/>
4235 This function should return a bit vector of the desired
4236 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>.
4237 This will determine if the entire iteration should be aborted
4238 (the <code>JVMTI_VISIT_OBJECTS</code> flag is ignored).
4239 <p/>
4240 See the <internallink id="heapCallbacks">heap callback
4241 function restrictions</internallink>.
4242 </description>
4243 <parameters>
4244 <param id="class_tag">
4245 <jlong/>
4246 <description>
4247 The tag of the class of the String class (zero if the class is not tagged).
4248 <issue>Is this needed?</issue>
4249 </description>
4250 </param>
4251 <param id="size">
4252 <jlong/>
4253 <description>
4254 Size of the string (in bytes).
4255 See <functionlink id="GetObjectSize"/>.
4256 </description>
4257 </param>
4258 <param id="tag_ptr">
4259 <outptr><jlong/></outptr>
4260 <description>
4261 Points to the tag of the String object, or zero if the object is not
4262 tagged.
4263 To set the tag value to be associated with the object
4264 the agent sets the <code>jlong</code> pointed to by the parameter.
4265 </description>
4266 </param>
4267 <param id="value">
4268 <vmbuf><jchar/></vmbuf>
4269 <description>
4270 The value of the String, encoded as a Unicode string.
4271 </description>
4272 </param>
4273 <param id="value_length">
4274 <jint/>
4275 <description>
4276 The length of the string.
4277 The length is equal to the number of 16-bit Unicode
4278 characters in the string.
4279 </description>
4280 </param>
4281 <param id="user_data">
4282 <outptr><void/></outptr>
4283 <description>
4284 The user supplied data that was passed into the iteration function.
4285 </description>
4286 </param>
4287 </parameters>
4288 </callback>
4291 <callback id="jvmtiReservedCallback" since="1.1">
4292 <jint/>
4293 <synopsis>reserved for future use Callback</synopsis>
4294 <description>
4295 Placeholder -- reserved for future use.
4296 </description>
4297 <parameters>
4298 </parameters>
4299 </callback>
4301 <function id="FollowReferences" num="115" since="1.1">
4302 <synopsis>Follow References</synopsis>
4303 <description>
4304 This function initiates a traversal over the objects that are
4305 directly and indirectly reachable from the specified object or,
4306 if <code>initial_object</code> is not specified, all objects
4307 reachable from the heap roots.
4308 The heap root are the set of system classes,
4309 JNI globals, references from thread stacks, and other objects used as roots
4310 for the purposes of garbage collection.
4311 <p/>
4312 This function operates by traversing the reference graph.
4313 Let <i>A</i>, <i>B</i>, ... represent objects.
4314 When a reference from <i>A</i> to <i>B</i> is traversed,
4315 when a reference from a heap root to <i>B</i> is traversed,
4316 or when <i>B</i> is specified as the <paramlink id="initial_object"/>,
4317 then <i>B</i> is said to be <i>visited</i>.
4318 A reference from <i>A</i> to <i>B</i> is not traversed until <i>A</i>
4319 is visited.
4320 References are reported in the same order that the references are traversed.
4321 Object references are reported by invoking the agent supplied
4322 callback function <functionlink id="jvmtiHeapReferenceCallback"/>.
4323 In a reference from <i>A</i> to <i>B</i>, <i>A</i> is known
4324 as the <i>referrer</i> and <i>B</i> as the <i>referree</i>.
4325 The callback is invoked exactly once for each reference from a referrer;
4326 this is true even if there are reference cycles or multiple paths to
4327 the referrer.
4328 There may be more than one reference between a referrer and a referree,
4329 each reference is reported.
4330 These references may be distinguished by examining the
4331 <datalink
4332 id="jvmtiHeapReferenceCallback.reference_kind"><code>reference_kind</code></datalink>
4333 and
4334 <datalink
4335 id="jvmtiHeapReferenceCallback.reference_info"><code>reference_info</code></datalink>
4336 parameters of the <functionlink id="jvmtiHeapReferenceCallback"/> callback.
4337 <p/>
4338 This function reports a Java programming language view of object references,
4339 not a virtual machine implementation view. The following object references
4340 are reported when they are non-null:
4341 <ul>
4342 <li>Instance objects report references to each non-primitive instance fields
4343 (including inherited fields).</li>
4344 <li>Instance objects report a reference to the object type (class).</li>
4345 <li>Classes report a reference to the superclass and directly
4346 implemented/extended interfaces.</li>
4347 <li>Classes report a reference to the class loader, protection domain,
4348 signers, and resolved entries in the constant pool.</li>
4349 <li>Classes report a reference to each directly declared non-primitive
4350 static field.</li>
4351 <li>Arrays report a reference to the array type (class) and each
4352 array element.</li>
4353 <li>Primitive arrays report a reference to the array type.</li>
4354 </ul>
4355 <p/>
4356 This function can also be used to examine primitive (non-object) values.
4357 The primitive value of an array or String
4358 is reported after the object has been visited;
4359 it is reported by invoking the agent supplied callback function
4360 <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4361 <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4362 A primitive field
4363 is reported after the object with that field is visited;
4364 it is reported by invoking the agent supplied callback function
4365 <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4366 <p/>
4367 Whether a callback is provided or is <code>NULL</code> only determines
4368 whether the callback will be invoked, it does not influence
4369 which objects are visited nor does it influence whether other callbacks
4370 will be invoked.
4371 However, the
4372 <datalink id="jvmtiHeapVisitControl">visit control flags</datalink>
4373 returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4374 do determine if the objects referenced by the
4375 current object as visited.
4376 The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4377 and <paramlink id="klass"/> provided as parameters to this function
4378 do not control which objects are visited but they do control which
4379 objects and primitive values are reported by the callbacks.
4380 For example, if the only callback that was set is
4381 <paramlink id="array_primitive_value_callback"/> and <code>klass</code>
4382 is set to the array of bytes class, then only arrays of byte will be
4383 reported.
4384 The table below summarizes this:
4385 <p/>
4386 <table>
4387 <tr>
4388 <th/>
4389 <th>
4390 Controls objects visited
4391 </th>
4392 <th>
4393 Controls objects reported
4394 </th>
4395 <th>
4396 Controls primitives reported
4397 </th>
4398 </tr>
4399 <tr>
4400 <th align="left">
4401 the
4402 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4403 returned by <functionlink id="jvmtiHeapReferenceCallback"/>
4404 </th>
4405 <td>
4406 <b>Yes</b>
4407 </td>
4408 <td>
4409 <b>Yes</b>, since visits are controlled
4410 </td>
4411 <td>
4412 <b>Yes</b>, since visits are controlled
4413 </td>
4414 </tr>
4415 <tr>
4416 <th align="left">
4417 <fieldlink id="object_reference_callback" struct="jvmtiHeapCallbacks"/>
4418 in <paramlink id="callbacks"/> set
4419 </th>
4420 <td>
4421 No
4422 </td>
4423 <td>
4424 <b>Yes</b>
4425 </td>
4426 <td>
4427 No
4428 </td>
4429 </tr>
4430 <tr>
4431 <th align="left">
4432 <paramlink id="heap_filter"/>
4433 </th>
4434 <td>
4435 No
4436 </td>
4437 <td>
4438 <b>Yes</b>
4439 </td>
4440 <td>
4441 <b>Yes</b>
4442 </td>
4443 </tr>
4444 <tr>
4445 <th align="left">
4446 <paramlink id="klass"/>
4447 </th>
4448 <td>
4449 No
4450 </td>
4451 <td>
4452 <b>Yes</b>
4453 </td>
4454 <td>
4455 <b>Yes</b>
4456 </td>
4457 </tr>
4458 </table>
4459 <p/>
4460 During the execution of this function the state of the heap
4461 does not change: no objects are allocated, no objects are
4462 garbage collected, and the state of objects (including
4463 held values) does not change.
4464 As a result, threads executing Java
4465 programming language code, threads attempting to resume the
4466 execution of Java programming language code, and threads
4467 attempting to execute JNI functions are typically stalled.
4468 </description>
4469 <origin>new</origin>
4470 <capabilities>
4471 <required id="can_tag_objects"></required>
4472 </capabilities>
4473 <parameters>
4474 <param id="heap_filter">
4475 <jint/>
4476 <description>
4477 This bit vector of
4478 <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4479 restricts the objects for which the callback function is called.
4480 This applies to both the object and primitive callbacks.
4481 </description>
4482 </param>
4483 <param id="klass">
4484 <ptrtype>
4485 <jclass/>
4486 <nullok>callbacks are not limited to instances of a particular
4487 class</nullok>
4488 </ptrtype>
4489 <description>
4490 Callbacks are only reported when the object is an instance of
4491 this class.
4492 Objects which are instances of a subclass of <code>klass</code>
4493 are not reported.
4494 If <code>klass</code> is an interface, no objects are reported.
4495 This applies to both the object and primitive callbacks.
4496 </description>
4497 </param>
4498 <param id="initial_object">
4499 <ptrtype>
4500 <jobject/>
4501 <nullok>references are followed from the heap roots</nullok>
4502 </ptrtype>
4503 <description>
4504 The object to follow
4505 </description>
4506 </param>
4507 <param id="callbacks">
4508 <inptr>
4509 <struct>jvmtiHeapCallbacks</struct>
4510 </inptr>
4511 <description>
4512 Structure defining the set of callback functions.
4513 </description>
4514 </param>
4515 <param id="user_data">
4516 <inbuf>
4517 <void/>
4518 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4519 </inbuf>
4520 <description>
4521 User supplied data to be passed to the callback.
4522 </description>
4523 </param>
4524 </parameters>
4525 <errors>
4526 <error id="JVMTI_ERROR_INVALID_CLASS">
4527 <paramlink id="klass"/> is not a valid class.
4528 </error>
4529 <error id="JVMTI_ERROR_INVALID_OBJECT">
4530 <paramlink id="initial_object"/> is not a valid object.
4531 </error>
4532 </errors>
4533 </function>
4536 <function id="IterateThroughHeap" num="116" since="1.1">
4537 <synopsis>Iterate Through Heap</synopsis>
4538 <description>
4539 Initiate an iteration over all objects in the heap.
4540 This includes both reachable and
4541 unreachable objects. Objects are visited in no particular order.
4542 <p/>
4543 Heap objects are reported by invoking the agent supplied
4544 callback function <functionlink id="jvmtiHeapIterationCallback"/>.
4545 References between objects are not reported.
4546 If only reachable objects are desired, or if object reference information
4547 is needed, use <functionlink id="FollowReferences"/>.
4548 <p/>
4549 This function can also be used to examine primitive (non-object) values.
4550 The primitive value of an array or String
4551 is reported after the object has been visited;
4552 it is reported by invoking the agent supplied callback function
4553 <functionlink id="jvmtiArrayPrimitiveValueCallback"/> or
4554 <functionlink id="jvmtiStringPrimitiveValueCallback"/>.
4555 A primitive field
4556 is reported after the object with that field is visited;
4557 it is reported by invoking the agent supplied
4558 callback function
4559 <functionlink id="jvmtiPrimitiveFieldCallback"/>.
4560 <p/>
4561 Unless the iteration is aborted by the
4562 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4563 returned by a callback, all objects in the heap are visited.
4564 Whether a callback is provided or is <code>NULL</code> only determines
4565 whether the callback will be invoked, it does not influence
4566 which objects are visited nor does it influence whether other callbacks
4567 will be invoked.
4568 The <datalink id="jvmtiHeapFilter">heap filter flags</datalink>
4569 and <paramlink id="klass"/> provided as parameters to this function
4570 do not control which objects are visited but they do control which
4571 objects and primitive values are reported by the callbacks.
4572 For example, if the only callback that was set is
4573 <paramlink id="array_primitive_value_callback"/> and <code>klass</code>
4574 is set to the array of bytes class, then only arrays of byte will be
4575 reported. The table below summarizes this (contrast this with
4576 <functionlink id="FollowReferences"/>):
4577 <p/>
4578 <table>
4579 <tr>
4580 <th/>
4581 <th>
4582 Controls objects visited
4583 </th>
4584 <th>
4585 Controls objects reported
4586 </th>
4587 <th>
4588 Controls primitives reported
4589 </th>
4590 </tr>
4591 <tr>
4592 <th align="left">
4593 the
4594 <datalink id="jvmtiHeapVisitControl">Heap Visit Control Flags</datalink>
4595 returned by <functionlink id="jvmtiHeapIterationCallback"/>
4596 </th>
4597 <td>
4598 No<br/>(unless they abort the iteration)
4599 </td>
4600 <td>
4601 No<br/>(unless they abort the iteration)
4602 </td>
4603 <td>
4604 No<br/>(unless they abort the iteration)
4605 </td>
4606 </tr>
4607 <tr>
4608 <th align="left">
4609 <fieldlink id="object_callback" struct="jvmtiHeapCallbacks"/>
4610 in <paramlink id="callbacks"/> set
4611 </th>
4612 <td>
4613 No
4614 </td>
4615 <td>
4616 <b>Yes</b>
4617 </td>
4618 <td>
4619 No
4620 </td>
4621 </tr>
4622 <tr>
4623 <th align="left">
4624 <paramlink id="heap_filter"/>
4625 </th>
4626 <td>
4627 No
4628 </td>
4629 <td>
4630 <b>Yes</b>
4631 </td>
4632 <td>
4633 <b>Yes</b>
4634 </td>
4635 </tr>
4636 <tr>
4637 <th align="left">
4638 <paramlink id="klass"/>
4639 </th>
4640 <td>
4641 No
4642 </td>
4643 <td>
4644 <b>Yes</b>
4645 </td>
4646 <td>
4647 <b>Yes</b>
4648 </td>
4649 </tr>
4650 </table>
4651 <p/>
4652 During the execution of this function the state of the heap
4653 does not change: no objects are allocated, no objects are
4654 garbage collected, and the state of objects (including
4655 held values) does not change.
4656 As a result, threads executing Java
4657 programming language code, threads attempting to resume the
4658 execution of Java programming language code, and threads
4659 attempting to execute JNI functions are typically stalled.
4660 </description>
4661 <origin>new</origin>
4662 <capabilities>
4663 <required id="can_tag_objects"></required>
4664 </capabilities>
4665 <parameters>
4666 <param id="heap_filter">
4667 <jint/>
4668 <description>
4669 This bit vector of
4670 <datalink id="jvmtiHeapFilter">heap filter flags</datalink>.
4671 restricts the objects for which the callback function is called.
4672 This applies to both the object and primitive callbacks.
4673 </description>
4674 </param>
4675 <param id="klass">
4676 <ptrtype>
4677 <jclass/>
4678 <nullok>callbacks are not limited to instances of a particular class</nullok>
4679 </ptrtype>
4680 <description>
4681 Callbacks are only reported when the object is an instance of
4682 this class.
4683 Objects which are instances of a subclass of <code>klass</code>
4684 are not reported.
4685 If <code>klass</code> is an interface, no objects are reported.
4686 This applies to both the object and primitive callbacks.
4687 </description>
4688 </param>
4689 <param id="callbacks">
4690 <inptr>
4691 <struct>jvmtiHeapCallbacks</struct>
4692 </inptr>
4693 <description>
4694 Structure defining the set callback functions.
4695 </description>
4696 </param>
4697 <param id="user_data">
4698 <inbuf>
4699 <void/>
4700 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
4701 </inbuf>
4702 <description>
4703 User supplied data to be passed to the callback.
4704 </description>
4705 </param>
4706 </parameters>
4707 <errors>
4708 <error id="JVMTI_ERROR_INVALID_CLASS">
4709 <paramlink id="klass"/> is not a valid class.
4710 </error>
4711 </errors>
4712 </function>
4714 <function id="GetTag" phase="start" num="106">
4715 <synopsis>Get Tag</synopsis>
4716 <description>
4717 Retrieve the tag associated with an object.
4718 The tag is a long value typically used to store a
4719 unique identifier or pointer to object information.
4720 The tag is set with
4721 <functionlink id="SetTag"></functionlink>.
4722 Objects for which no tags have been set return a
4723 tag value of zero.
4724 </description>
4725 <origin>new</origin>
4726 <capabilities>
4727 <required id="can_tag_objects"></required>
4728 </capabilities>
4729 <parameters>
4730 <param id="object">
4731 <jobject/>
4732 <description>
4733 The object whose tag is to be retrieved.
4734 </description>
4735 </param>
4736 <param id="tag_ptr">
4737 <outptr><jlong/></outptr>
4738 <description>
4739 On return, the referenced long is set to the value
4740 of the tag.
4741 </description>
4742 </param>
4743 </parameters>
4744 <errors>
4745 </errors>
4746 </function>
4748 <function id="SetTag" phase="start" num="107">
4749 <synopsis>Set Tag</synopsis>
4750 <description>
4751 Set the tag associated with an object.
4752 The tag is a long value typically used to store a
4753 unique identifier or pointer to object information.
4754 The tag is visible with
4755 <functionlink id="GetTag"></functionlink>.
4756 </description>
4757 <origin>new</origin>
4758 <capabilities>
4759 <required id="can_tag_objects"></required>
4760 </capabilities>
4761 <parameters>
4762 <param id="object">
4763 <jobject/>
4764 <description>
4765 The object whose tag is to be set.
4766 </description>
4767 </param>
4768 <param id="tag">
4769 <jlong/>
4770 <description>
4771 The new value of the tag.
4772 </description>
4773 </param>
4774 </parameters>
4775 <errors>
4776 </errors>
4777 </function>
4779 <function id="GetObjectsWithTags" num="114">
4780 <synopsis>Get Objects With Tags</synopsis>
4781 <description>
4782 Return objects in the heap with the specified tags.
4783 The format is parallel arrays of objects and tags.
4784 </description>
4785 <origin>new</origin>
4786 <capabilities>
4787 <required id="can_tag_objects"></required>
4788 </capabilities>
4789 <parameters>
4790 <param id="tag_count">
4791 <jint min="0"/>
4792 <description>
4793 Number of tags to scan for.
4794 </description>
4795 </param>
4796 <param id="tags">
4797 <inbuf incount="tag_count">
4798 <jlong/>
4799 </inbuf>
4800 <description>
4801 Scan for objects with these tags.
4802 Zero is not permitted in this array.
4803 </description>
4804 </param>
4805 <param id="count_ptr">
4806 <outptr>
4807 <jint/>
4808 </outptr>
4809 <description>
4810 Return the number of objects with any of the tags
4811 in <paramlink id="tags"/>.
4812 </description>
4813 </param>
4814 <param id="object_result_ptr">
4815 <allocbuf outcount="count_ptr">
4816 <jobject/>
4817 <nullok>this information is not returned</nullok>
4818 </allocbuf>
4819 <description>
4820 Returns the array of objects with any of the tags
4821 in <paramlink id="tags"/>.
4822 </description>
4823 </param>
4824 <param id="tag_result_ptr">
4825 <allocbuf outcount="count_ptr">
4826 <jlong/>
4827 <nullok>this information is not returned</nullok>
4828 </allocbuf>
4829 <description>
4830 For each object in <paramlink id="object_result_ptr"/>,
4831 return the tag at the corresponding index.
4832 </description>
4833 </param>
4834 </parameters>
4835 <errors>
4836 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
4837 Zero is present in <paramlink id="tags"></paramlink>.
4838 </error>
4839 </errors>
4840 </function>
4842 <function id="ForceGarbageCollection" num="108">
4843 <synopsis>Force Garbage Collection</synopsis>
4844 <description>
4845 Force the VM to perform a garbage collection.
4846 The garbage collection is as complete as possible.
4847 This function does not cause finalizers to be run.
4848 This function does not return until the garbage collection
4849 is finished.
4850 <p/>
4851 Although garbage collection is as complete
4852 as possible there is no guarantee that all
4853 <eventlink id="ObjectFree"/>
4854 events will have been
4855 sent by the time that this function
4856 returns. In particular, an object may be
4857 prevented from being freed because it
4858 is awaiting finalization.
4859 </description>
4860 <origin>new</origin>
4861 <capabilities>
4862 </capabilities>
4863 <parameters>
4864 </parameters>
4865 <errors>
4866 </errors>
4867 </function>
4870 </category>
4872 <category id="Heap_1_0" label="Heap (1.0)">
4873 <intro>
4874 <b>
4875 These functions and data types were introduced in the original
4876 <jvmti/> version 1.0 and have been superseded by more
4877 </b>
4878 <internallink id="Heap"><b>powerful and flexible versions</b></internallink>
4879 <b>
4880 which:
4881 </b>
4882 <ul>
4883 <li>
4884 <b>
4885 Allow access to primitive values (the value of Strings, arrays,
4886 and primitive fields)
4887 </b>
4888 </li>
4889 <li>
4890 <b>
4891 Allow the tag of the referrer to be set, thus enabling more
4892 efficient localized reference graph building
4893 </b>
4894 </li>
4895 <li>
4896 <b>
4897 Provide more extensive filtering abilities
4898 </b>
4899 </li>
4900 <li>
4901 <b>
4902 Are extensible, allowing their abilities to grow in future versions of <jvmti/>
4903 </b>
4904 </li>
4905 </ul>
4906 <p/>
4907 <b>Please use the </b>
4908 <internallink id="Heap"><b>current Heap functions</b></internallink>.
4909 <p/>
4910 <constants id="jvmtiHeapObjectFilter" label="Heap Object Filter Enumeration" kind="enum">
4911 <constant id="JVMTI_HEAP_OBJECT_TAGGED" num="1">
4912 Tagged objects only.
4913 </constant>
4914 <constant id="JVMTI_HEAP_OBJECT_UNTAGGED" num="2">
4915 Untagged objects only.
4916 </constant>
4917 <constant id="JVMTI_HEAP_OBJECT_EITHER" num="3">
4918 Either tagged or untagged objects.
4919 </constant>
4920 </constants>
4922 <constants id="jvmtiHeapRootKind" label="Heap Root Kind Enumeration" kind="enum">
4923 <constant id="JVMTI_HEAP_ROOT_JNI_GLOBAL" num="1">
4924 JNI global reference.
4925 </constant>
4926 <constant id="JVMTI_HEAP_ROOT_SYSTEM_CLASS" num="2">
4927 System class.
4928 </constant>
4929 <constant id="JVMTI_HEAP_ROOT_MONITOR" num="3">
4930 Monitor.
4931 </constant>
4932 <constant id="JVMTI_HEAP_ROOT_STACK_LOCAL" num="4">
4933 Stack local.
4934 </constant>
4935 <constant id="JVMTI_HEAP_ROOT_JNI_LOCAL" num="5">
4936 JNI local reference.
4937 </constant>
4938 <constant id="JVMTI_HEAP_ROOT_THREAD" num="6">
4939 Thread.
4940 </constant>
4941 <constant id="JVMTI_HEAP_ROOT_OTHER" num="7">
4942 Other.
4943 </constant>
4944 </constants>
4946 <constants id="jvmtiObjectReferenceKind" label="Object Reference Enumeration" kind="enum">
4947 <constant id="JVMTI_REFERENCE_CLASS" num="1">
4948 Reference from an object to its class.
4949 </constant>
4950 <constant id="JVMTI_REFERENCE_FIELD" num="2">
4951 Reference from an object to the value of one of its instance fields.
4952 For references of this kind the <code>referrer_index</code>
4953 parameter to the <internallink id="jvmtiObjectReferenceCallback">
4954 jvmtiObjectReferenceCallback</internallink> is the index of the
4955 the instance field. The index is based on the order of all the
4956 object's fields. This includes all fields of the directly declared
4957 static and instance fields in the class, and includes all fields (both
4958 public and private) fields declared in superclasses and superinterfaces.
4959 The index is thus calculated by summing the index of the field in the directly
4960 declared class (see <functionlink id="GetClassFields"/>), with the total
4961 number of fields (both public and private) declared in all superclasses
4962 and superinterfaces. The index starts at zero.
4963 </constant>
4964 <constant id="JVMTI_REFERENCE_ARRAY_ELEMENT" num="3">
4965 Reference from an array to one of its elements.
4966 For references of this kind the <code>referrer_index</code>
4967 parameter to the <internallink id="jvmtiObjectReferenceCallback">
4968 jvmtiObjectReferenceCallback</internallink> is the array index.
4969 </constant>
4970 <constant id="JVMTI_REFERENCE_CLASS_LOADER" num="4">
4971 Reference from a class to its class loader.
4972 </constant>
4973 <constant id="JVMTI_REFERENCE_SIGNERS" num="5">
4974 Reference from a class to its signers array.
4975 </constant>
4976 <constant id="JVMTI_REFERENCE_PROTECTION_DOMAIN" num="6">
4977 Reference from a class to its protection domain.
4978 </constant>
4979 <constant id="JVMTI_REFERENCE_INTERFACE" num="7">
4980 Reference from a class to one of its interfaces.
4981 </constant>
4982 <constant id="JVMTI_REFERENCE_STATIC_FIELD" num="8">
4983 Reference from a class to the value of one of its static fields.
4984 For references of this kind the <code>referrer_index</code>
4985 parameter to the <internallink id="jvmtiObjectReferenceCallback">
4986 jvmtiObjectReferenceCallback</internallink> is the index of the
4987 the static field. The index is based on the order of all the
4988 object's fields. This includes all fields of the directly declared
4989 static and instance fields in the class, and includes all fields (both
4990 public and private) fields declared in superclasses and superinterfaces.
4991 The index is thus calculated by summing the index of the field in the directly
4992 declared class (see <functionlink id="GetClassFields"/>), with the total
4993 number of fields (both public and private) declared in all superclasses
4994 and superinterfaces. The index starts at zero.
4995 Note: this definition differs from that in the <jvmti/> 1.0 Specification.
4996 <rationale>No known implementations used the 1.0 definition.</rationale>
4997 </constant>
4998 <constant id="JVMTI_REFERENCE_CONSTANT_POOL" num="9">
4999 Reference from a class to a resolved entry in the constant pool.
5000 For references of this kind the <code>referrer_index</code>
5001 parameter to the <internallink id="jvmtiObjectReferenceCallback">
5002 jvmtiObjectReferenceCallback</internallink> is the index into
5003 constant pool table of the class, starting at 1. See
5004 <vmspec chapter="4.4"/>.
5005 </constant>
5006 </constants>
5008 <constants id="jvmtiIterationControl" label="Iteration Control Enumeration" kind="enum">
5009 <constant id="JVMTI_ITERATION_CONTINUE" num="1">
5010 Continue the iteration.
5011 If this is a reference iteration, follow the references of this object.
5012 </constant>
5013 <constant id="JVMTI_ITERATION_IGNORE" num="2">
5014 Continue the iteration.
5015 If this is a reference iteration, ignore the references of this object.
5016 </constant>
5017 <constant id="JVMTI_ITERATION_ABORT" num="0">
5018 Abort the iteration.
5019 </constant>
5020 </constants>
5021 </intro>
5023 <callback id="jvmtiHeapObjectCallback">
5024 <enum>jvmtiIterationControl</enum>
5025 <synopsis>Heap Object Callback</synopsis>
5026 <description>
5027 Agent supplied callback function.
5028 Describes (but does not pass in) an object in the heap.
5029 <p/>
5030 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5031 or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5032 <p/>
5033 See the <internallink id="heapCallbacks">heap callback
5034 function restrictions</internallink>.
5035 </description>
5036 <parameters>
5037 <param id="class_tag">
5038 <jlong/>
5039 <description>
5040 The tag of the class of object (zero if the class is not tagged).
5041 If the object represents a runtime class,
5042 the <code>class_tag</code> is the tag
5043 associated with <code>java.lang.Class</code>
5044 (zero if <code>java.lang.Class</code> is not tagged).
5045 </description>
5046 </param>
5047 <param id="size">
5048 <jlong/>
5049 <description>
5050 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5051 </description>
5052 </param>
5053 <param id="tag_ptr">
5054 <outptr><jlong/></outptr>
5055 <description>
5056 The object tag value, or zero if the object is not tagged.
5057 To set the tag value to be associated with the object
5058 the agent sets the <code>jlong</code> pointed to by the parameter.
5059 </description>
5060 </param>
5061 <param id="user_data">
5062 <outptr><void/></outptr>
5063 <description>
5064 The user supplied data that was passed into the iteration function.
5065 </description>
5066 </param>
5067 </parameters>
5068 </callback>
5070 <callback id="jvmtiHeapRootCallback">
5071 <enum>jvmtiIterationControl</enum>
5072 <synopsis>Heap Root Object Callback</synopsis>
5073 <description>
5074 Agent supplied callback function.
5075 Describes (but does not pass in) an object that is a root for the purposes
5076 of garbage collection.
5077 <p/>
5078 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5079 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5080 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5081 <p/>
5082 See the <internallink id="heapCallbacks">heap callback
5083 function restrictions</internallink>.
5084 </description>
5085 <parameters>
5086 <param id="root_kind">
5087 <enum>jvmtiHeapRootKind</enum>
5088 <description>
5089 The kind of heap root.
5090 </description>
5091 </param>
5092 <param id="class_tag">
5093 <jlong/>
5094 <description>
5095 The tag of the class of object (zero if the class is not tagged).
5096 If the object represents a runtime class, the <code>class_tag</code> is the tag
5097 associated with <code>java.lang.Class</code>
5098 (zero if <code>java.lang.Class</code> is not tagged).
5099 </description>
5100 </param>
5101 <param id="size">
5102 <jlong/>
5103 <description>
5104 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5105 </description>
5106 </param>
5107 <param id="tag_ptr">
5108 <outptr><jlong/></outptr>
5109 <description>
5110 The object tag value, or zero if the object is not tagged.
5111 To set the tag value to be associated with the object
5112 the agent sets the <code>jlong</code> pointed to by the parameter.
5113 </description>
5114 </param>
5115 <param id="user_data">
5116 <outptr><void/></outptr>
5117 <description>
5118 The user supplied data that was passed into the iteration function.
5119 </description>
5120 </param>
5121 </parameters>
5122 </callback>
5124 <callback id="jvmtiStackReferenceCallback">
5125 <enum>jvmtiIterationControl</enum>
5126 <synopsis>Stack Reference Object Callback</synopsis>
5127 <description>
5128 Agent supplied callback function.
5129 Describes (but does not pass in) an object on the stack that is a root for
5130 the purposes of garbage collection.
5131 <p/>
5132 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5133 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5134 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5135 <p/>
5136 See the <internallink id="heapCallbacks">heap callback
5137 function restrictions</internallink>.
5138 </description>
5139 <parameters>
5140 <param id="root_kind">
5141 <enum>jvmtiHeapRootKind</enum>
5142 <description>
5143 The kind of root (either <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5144 <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>).
5145 </description>
5146 </param>
5147 <param id="class_tag">
5148 <jlong/>
5149 <description>
5150 The tag of the class of object (zero if the class is not tagged).
5151 If the object represents a runtime class, the <code>class_tag</code> is the tag
5152 associated with <code>java.lang.Class</code>
5153 (zero if <code>java.lang.Class</code> is not tagged).
5154 </description>
5155 </param>
5156 <param id="size">
5157 <jlong/>
5158 <description>
5159 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
5160 </description>
5161 </param>
5162 <param id="tag_ptr">
5163 <outptr><jlong/></outptr>
5164 <description>
5165 The object tag value, or zero if the object is not tagged.
5166 To set the tag value to be associated with the object
5167 the agent sets the <code>jlong</code> pointed to by the parameter.
5168 </description>
5169 </param>
5170 <param id="thread_tag">
5171 <jlong/>
5172 <description>
5173 The tag of the thread corresponding to this stack, zero if not tagged.
5174 </description>
5175 </param>
5176 <param id="depth">
5177 <jint/>
5178 <description>
5179 The depth of the frame.
5180 </description>
5181 </param>
5182 <param id="method">
5183 <jmethodID/>
5184 <description>
5185 The method executing in this frame.
5186 </description>
5187 </param>
5188 <param id="slot">
5189 <jint/>
5190 <description>
5191 The slot number.
5192 </description>
5193 </param>
5194 <param id="user_data">
5195 <outptr><void/></outptr>
5196 <description>
5197 The user supplied data that was passed into the iteration function.
5198 </description>
5199 </param>
5200 </parameters>
5201 </callback>
5203 <callback id="jvmtiObjectReferenceCallback">
5204 <enum>jvmtiIterationControl</enum>
5205 <synopsis>Object Reference Callback</synopsis>
5206 <description>
5207 Agent supplied callback function.
5208 Describes a reference from an object (the referrer) to another object
5209 (the referree).
5210 <p/>
5211 Return value should be <code>JVMTI_ITERATION_CONTINUE</code> to continue iteration,
5212 <code>JVMTI_ITERATION_IGNORE</code> to continue iteration without pursuing
5213 references from referree object or <code>JVMTI_ITERATION_ABORT</code> to stop iteration.
5214 <p/>
5215 See the <internallink id="heapCallbacks">heap callback
5216 function restrictions</internallink>.
5217 </description>
5218 <parameters>
5219 <param id="reference_kind">
5220 <enum>jvmtiObjectReferenceKind</enum>
5221 <description>
5222 The type of reference.
5223 </description>
5224 </param>
5225 <param id="class_tag">
5226 <jlong/>
5227 <description>
5228 The tag of the class of referree object (zero if the class is not tagged).
5229 If the referree object represents a runtime class,
5230 the <code>class_tag</code> is the tag
5231 associated with <code>java.lang.Class</code>
5232 (zero if <code>java.lang.Class</code> is not tagged).
5233 </description>
5234 </param>
5235 <param id="size">
5236 <jlong/>
5237 <description>
5238 Size of the referree object (in bytes).
5239 See <functionlink id="GetObjectSize"/>.
5240 </description>
5241 </param>
5242 <param id="tag_ptr">
5243 <outptr><jlong/></outptr>
5244 <description>
5245 The referree object tag value, or zero if the object is not
5246 tagged.
5247 To set the tag value to be associated with the object
5248 the agent sets the <code>jlong</code> pointed to by the parameter.
5249 </description>
5250 </param>
5251 <param id="referrer_tag">
5252 <jlong/>
5253 <description>
5254 The tag of the referrer object, or zero if the referrer
5255 object is not tagged.
5256 </description>
5257 </param>
5258 <param id="referrer_index">
5259 <jint/>
5260 <description>
5261 For references of type <code>JVMTI_REFERENCE_FIELD</code> or
5262 <code>JVMTI_REFERENCE_STATIC_FIELD</code> the index
5263 of the field in the referrer object. The index is based on the
5264 order of all the object's fields - see <internallink
5265 id="JVMTI_REFERENCE_FIELD">JVMTI_REFERENCE_FIELD</internallink>
5266 or <internallink
5267 id="JVMTI_REFERENCE_STATIC_FIELD">JVMTI_REFERENCE_STATIC_FIELD
5268 </internallink> for further description.
5269 <p/>
5270 For references of type <code>JVMTI_REFERENCE_ARRAY_ELEMENT</code>
5271 the array index - see <internallink id="JVMTI_REFERENCE_ARRAY_ELEMENT">
5272 JVMTI_REFERENCE_ARRAY_ELEMENT</internallink> for further description.
5273 <p/>
5274 For references of type <code>JVMTI_REFERENCE_CONSTANT_POOL</code>
5275 the index into the constant pool of the class - see
5276 <internallink id="JVMTI_REFERENCE_CONSTANT_POOL">
5277 JVMTI_REFERENCE_CONSTANT_POOL</internallink> for further
5278 description.
5279 <p/>
5280 For references of other kinds the <code>referrer_index</code> is
5281 <code>-1</code>.
5282 </description>
5283 </param>
5284 <param id="user_data">
5285 <outptr><void/></outptr>
5286 <description>
5287 The user supplied data that was passed into the iteration function.
5288 </description>
5289 </param>
5290 </parameters>
5291 </callback>
5293 <function id="IterateOverObjectsReachableFromObject" num="109">
5294 <synopsis>Iterate Over Objects Reachable From Object</synopsis>
5295 <description>
5296 This function iterates over all objects that are directly
5297 and indirectly reachable from the specified object.
5298 For each object <i>A</i> (known
5299 as the referrer) with a reference to object <i>B</i> the specified
5300 callback function is called to describe the object reference.
5301 The callback is called exactly once for each reference from a referrer;
5302 this is true even if there are reference cycles or multiple paths to
5303 the referrer.
5304 There may be more than one reference between a referrer and a referree,
5305 These may be distinguished by the
5306 <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5307 <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5308 The callback for an object will always occur after the callback for
5309 its referrer.
5310 <p/>
5311 See <functionlink id="FollowReferences"/> for the object
5312 references which are reported.
5313 <p/>
5314 During the execution of this function the state of the heap
5315 does not change: no objects are allocated, no objects are
5316 garbage collected, and the state of objects (including
5317 held values) does not change.
5318 As a result, threads executing Java
5319 programming language code, threads attempting to resume the
5320 execution of Java programming language code, and threads
5321 attempting to execute JNI functions are typically stalled.
5322 </description>
5323 <origin>new</origin>
5324 <capabilities>
5325 <required id="can_tag_objects"></required>
5326 </capabilities>
5327 <parameters>
5328 <param id="object">
5329 <jobject/>
5330 <description>
5331 The object
5332 </description>
5333 </param>
5334 <param id="object_reference_callback">
5335 <ptrtype>
5336 <struct>jvmtiObjectReferenceCallback</struct>
5337 </ptrtype>
5338 <description>
5339 The callback to be called to describe each
5340 object reference.
5341 </description>
5342 </param>
5343 <param id="user_data">
5344 <inbuf>
5345 <void/>
5346 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5347 </inbuf>
5348 <description>
5349 User supplied data to be passed to the callback.
5350 </description>
5351 </param>
5352 </parameters>
5353 <errors>
5354 </errors>
5355 </function>
5357 <function id="IterateOverReachableObjects" num="110">
5358 <synopsis>Iterate Over Reachable Objects</synopsis>
5359 <description>
5360 This function iterates over the root objects and all objects that
5361 are directly and indirectly reachable from the root objects.
5362 The root objects comprise the set of system classes,
5363 JNI globals, references from thread stacks, and other objects used as roots
5364 for the purposes of garbage collection.
5365 <p/>
5366 For each root the <paramlink id="heap_root_callback"></paramlink>
5367 or <paramlink id="stack_ref_callback"></paramlink> callback is called.
5368 An object can be a root object for more than one reason and in that case
5369 the appropriate callback is called for each reason.
5370 <p/>
5371 For each object reference the <paramlink id="object_ref_callback"></paramlink>
5372 callback function is called to describe the object reference.
5373 The callback is called exactly once for each reference from a referrer;
5374 this is true even if there are reference cycles or multiple paths to
5375 the referrer.
5376 There may be more than one reference between a referrer and a referree,
5377 These may be distinguished by the
5378 <datalink id="jvmtiObjectReferenceCallback.reference_kind"></datalink> and
5379 <datalink id="jvmtiObjectReferenceCallback.referrer_index"></datalink>.
5380 The callback for an object will always occur after the callback for
5381 its referrer.
5382 <p/>
5383 See <functionlink id="FollowReferences"/> for the object
5384 references which are reported.
5385 <p/>
5386 Roots are always reported to the profiler before any object references
5387 are reported. In other words, the <paramlink id="object_ref_callback"></paramlink>
5388 callback will not be called until the appropriate callback has been called
5389 for all roots. If the <paramlink id="object_ref_callback"></paramlink> callback is
5390 specified as <code>NULL</code> then this function returns after
5391 reporting the root objects to the profiler.
5392 <p/>
5393 During the execution of this function the state of the heap
5394 does not change: no objects are allocated, no objects are
5395 garbage collected, and the state of objects (including
5396 held values) does not change.
5397 As a result, threads executing Java
5398 programming language code, threads attempting to resume the
5399 execution of Java programming language code, and threads
5400 attempting to execute JNI functions are typically stalled.
5401 </description>
5402 <origin>new</origin>
5403 <capabilities>
5404 <required id="can_tag_objects"></required>
5405 </capabilities>
5406 <parameters>
5407 <param id="heap_root_callback">
5408 <ptrtype>
5409 <struct>jvmtiHeapRootCallback</struct>
5410 <nullok>do not report heap roots</nullok>
5411 </ptrtype>
5412 <description>
5413 The callback function to be called for each heap root of type
5414 <code>JVMTI_HEAP_ROOT_JNI_GLOBAL</code>,
5415 <code>JVMTI_HEAP_ROOT_SYSTEM_CLASS</code>,
5416 <code>JVMTI_HEAP_ROOT_MONITOR</code>,
5417 <code>JVMTI_HEAP_ROOT_THREAD</code>, or
5418 <code>JVMTI_HEAP_ROOT_OTHER</code>.
5419 </description>
5420 </param>
5421 <param id="stack_ref_callback">
5422 <ptrtype>
5423 <struct>jvmtiStackReferenceCallback</struct>
5424 <nullok>do not report stack references</nullok>
5425 </ptrtype>
5426 <description>
5427 The callback function to be called for each heap root of
5428 <code>JVMTI_HEAP_ROOT_STACK_LOCAL</code> or
5429 <code>JVMTI_HEAP_ROOT_JNI_LOCAL</code>.
5430 </description>
5431 </param>
5432 <param id="object_ref_callback">
5433 <ptrtype>
5434 <struct>jvmtiObjectReferenceCallback</struct>
5435 <nullok>do not follow references from the root objects</nullok>
5436 </ptrtype>
5437 <description>
5438 The callback function to be called for each object reference.
5439 </description>
5440 </param>
5441 <param id="user_data">
5442 <inbuf>
5443 <void/>
5444 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5445 </inbuf>
5446 <description>
5447 User supplied data to be passed to the callback.
5448 </description>
5449 </param>
5450 </parameters>
5451 <errors>
5452 </errors>
5453 </function>
5455 <function id="IterateOverHeap" num="111">
5456 <synopsis>Iterate Over Heap</synopsis>
5457 <description>
5458 Iterate over all objects in the heap. This includes both reachable and
5459 unreachable objects.
5460 <p/>
5461 The <paramlink id="object_filter"></paramlink> parameter indicates the
5462 objects for which the callback function is called. If this parameter
5463 is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5464 called for every object that is tagged. If the parameter is
5465 <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5466 for objects that are not tagged. If the parameter
5467 is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5468 called for every object in the heap, irrespective of whether it is
5469 tagged or not.
5470 <p/>
5471 During the execution of this function the state of the heap
5472 does not change: no objects are allocated, no objects are
5473 garbage collected, and the state of objects (including
5474 held values) does not change.
5475 As a result, threads executing Java
5476 programming language code, threads attempting to resume the
5477 execution of Java programming language code, and threads
5478 attempting to execute JNI functions are typically stalled.
5479 </description>
5480 <origin>new</origin>
5481 <capabilities>
5482 <required id="can_tag_objects"></required>
5483 </capabilities>
5484 <parameters>
5485 <param id="object_filter">
5486 <enum>jvmtiHeapObjectFilter</enum>
5487 <description>
5488 Indicates the objects for which the callback function is called.
5489 </description>
5490 </param>
5491 <param id="heap_object_callback">
5492 <ptrtype>
5493 <struct>jvmtiHeapObjectCallback</struct>
5494 </ptrtype>
5495 <description>
5496 The iterator function to be called for each
5497 object matching the <paramlink id="object_filter"/>.
5498 </description>
5499 </param>
5500 <param id="user_data">
5501 <inbuf>
5502 <void/>
5503 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5504 </inbuf>
5505 <description>
5506 User supplied data to be passed to the callback.
5507 </description>
5508 </param>
5509 </parameters>
5510 <errors>
5511 </errors>
5512 </function>
5514 <function id="IterateOverInstancesOfClass" num="112">
5515 <synopsis>Iterate Over Instances Of Class</synopsis>
5516 <description>
5517 Iterate over all objects in the heap that are instances of the specified class.
5518 This includes direct instances of the specified class and
5519 instances of all subclasses of the specified class.
5520 This includes both reachable and unreachable objects.
5521 <p/>
5522 The <paramlink id="object_filter"></paramlink> parameter indicates the
5523 objects for which the callback function is called. If this parameter
5524 is <code>JVMTI_HEAP_OBJECT_TAGGED</code> then the callback will only be
5525 called for every object that is tagged. If the parameter is
5526 <code>JVMTI_HEAP_OBJECT_UNTAGGED</code> then the callback will only be
5527 called for objects that are not tagged. If the parameter
5528 is <code>JVMTI_HEAP_OBJECT_EITHER</code> then the callback will be
5529 called for every object in the heap, irrespective of whether it is
5530 tagged or not.
5531 <p/>
5532 During the execution of this function the state of the heap
5533 does not change: no objects are allocated, no objects are
5534 garbage collected, and the state of objects (including
5535 held values) does not change.
5536 As a result, threads executing Java
5537 programming language code, threads attempting to resume the
5538 execution of Java programming language code, and threads
5539 attempting to execute JNI functions are typically stalled.
5540 </description>
5541 <origin>new</origin>
5542 <capabilities>
5543 <required id="can_tag_objects"></required>
5544 </capabilities>
5545 <parameters>
5546 <param id="klass">
5547 <jclass/>
5548 <description>
5549 Iterate over objects of this class only.
5550 </description>
5551 </param>
5552 <param id="object_filter">
5553 <enum>jvmtiHeapObjectFilter</enum>
5554 <description>
5555 Indicates the objects for which the callback function is called.
5556 </description>
5557 </param>
5558 <param id="heap_object_callback">
5559 <ptrtype>
5560 <struct>jvmtiHeapObjectCallback</struct>
5561 </ptrtype>
5562 <description>
5563 The iterator function to be called for each
5564 <paramlink id="klass"/> instance matching
5565 the <paramlink id="object_filter"/>.
5566 </description>
5567 </param>
5568 <param id="user_data">
5569 <inbuf>
5570 <void/>
5571 <nullok><code>NULL</code> is passed as the user supplied data</nullok>
5572 </inbuf>
5573 <description>
5574 User supplied data to be passed to the callback.
5575 </description>
5576 </param>
5577 </parameters>
5578 <errors>
5579 </errors>
5580 </function>
5582 </category>
5584 <category id="local" label="Local Variable">
5586 <intro>
5587 These functions are used to retrieve or set the value of a local variable.
5588 The variable is identified by the depth of the frame containing its
5589 value and the variable's slot number within that frame.
5590 The mapping of variables to
5591 slot numbers can be obtained with the function
5592 <functionlink id="GetLocalVariableTable"></functionlink>.
5593 </intro>
5595 <function id="GetLocalObject" num="21">
5596 <synopsis>Get Local Variable - Object</synopsis>
5597 <description>
5598 This function can be used to retrieve the value of a local
5599 variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5600 </description>
5601 <origin>jvmdi</origin>
5602 <capabilities>
5603 <required id="can_access_local_variables"></required>
5604 </capabilities>
5605 <parameters>
5606 <param id="thread">
5607 <jthread null="current" frame="frame"/>
5608 <description>
5609 The thread of the frame containing the variable's value.
5610 </description>
5611 </param>
5612 <param id="depth">
5613 <jframeID thread="thread"/>
5614 <description>
5615 The depth of the frame containing the variable's value.
5616 </description>
5617 </param>
5618 <param id="slot">
5619 <jint/>
5620 <description>
5621 The variable's slot number.
5622 </description>
5623 </param>
5624 <param id="value_ptr">
5625 <outptr><jobject/></outptr>
5626 <description>
5627 On return, points to the variable's value.
5628 </description>
5629 </param>
5630 </parameters>
5631 <errors>
5632 <error id="JVMTI_ERROR_INVALID_SLOT">
5633 Invalid <code>slot</code>.
5634 </error>
5635 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5636 The variable type is not
5637 <code>Object</code> or a subclass of <code>Object</code>.
5638 </error>
5639 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5640 Not a visible frame
5641 </error>
5642 </errors>
5643 </function>
5645 <function id="GetLocalInstance" num="155" since="1.2">
5646 <synopsis>Get Local Instance</synopsis>
5647 <description>
5648 This function can be used to retrieve the value of the local object
5649 variable at slot 0 (the "<code>this</code>" object) from non-static
5650 frames. This function can retrieve the "<code>this</code>" object from
5651 native method frames, whereas <code>GetLocalObject()</code> would
5652 return <code>JVMTI_ERROR_OPAQUE_FRAME</code> in those cases.
5653 </description>
5654 <origin>new</origin>
5655 <capabilities>
5656 <required id="can_access_local_variables"></required>
5657 </capabilities>
5658 <parameters>
5659 <param id="thread">
5660 <jthread null="current" frame="frame"/>
5661 <description>
5662 The thread of the frame containing the variable's value.
5663 </description>
5664 </param>
5665 <param id="depth">
5666 <jframeID thread="thread"/>
5667 <description>
5668 The depth of the frame containing the variable's value.
5669 </description>
5670 </param>
5671 <param id="value_ptr">
5672 <outptr><jobject/></outptr>
5673 <description>
5674 On return, points to the variable's value.
5675 </description>
5676 </param>
5677 </parameters>
5678 <errors>
5679 <error id="JVMTI_ERROR_INVALID_SLOT">
5680 If the specified frame is a static method frame.
5681 </error>
5682 </errors>
5683 </function>
5684 <function id="GetLocalInt" num="22">
5685 <synopsis>Get Local Variable - Int</synopsis>
5686 <description>
5687 This function can be used to retrieve the value of a local
5688 variable whose type is <code>int</code>,
5689 <code>short</code>, <code>char</code>, <code>byte</code>, or
5690 <code>boolean</code>.
5691 </description>
5692 <origin>jvmdi</origin>
5693 <capabilities>
5694 <required id="can_access_local_variables"></required>
5695 </capabilities>
5696 <parameters>
5697 <param id="thread">
5698 <jthread null="current" frame="frame"/>
5699 <description>
5700 The thread of the frame containing the variable's value.
5701 </description>
5702 </param>
5703 <param id="depth">
5704 <jframeID thread="thread"/>
5705 <description>
5706 The depth of the frame containing the variable's value.
5707 </description>
5708 </param>
5709 <param id="slot">
5710 <jint/>
5711 <description>
5712 The variable's slot number.
5713 </description>
5714 </param>
5715 <param id="value_ptr">
5716 <outptr><jint/></outptr>
5717 <description>
5718 On return, points to the variable's value.
5719 </description>
5720 </param>
5721 </parameters>
5722 <errors>
5723 <error id="JVMTI_ERROR_INVALID_SLOT">
5724 Invalid <code>slot</code>.
5725 </error>
5726 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5727 The variable type is not
5728 <code>int</code>, <code>short</code>,
5729 <code>char</code>, <code>byte</code>, or
5730 <code>boolean</code>.
5731 </error>
5732 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5733 Not a visible frame
5734 </error>
5735 </errors>
5736 </function>
5738 <function id="GetLocalLong" num="23">
5739 <synopsis>Get Local Variable - Long</synopsis>
5740 <description>
5741 This function can be used to retrieve the value of a local
5742 variable whose type is <code>long</code>.
5743 </description>
5744 <origin>jvmdi</origin>
5745 <capabilities>
5746 <required id="can_access_local_variables"></required>
5747 </capabilities>
5748 <parameters>
5749 <param id="thread">
5750 <jthread null="current" frame="frame"/>
5751 <description>
5752 The thread of the frame containing the variable's value.
5753 </description>
5754 </param>
5755 <param id="depth">
5756 <jframeID thread="thread"/>
5757 <description>
5758 The depth of the frame containing the variable's value.
5759 </description>
5760 </param>
5761 <param id="slot">
5762 <jint/>
5763 <description>
5764 The variable's slot number.
5765 </description>
5766 </param>
5767 <param id="value_ptr">
5768 <outptr><jlong/></outptr>
5769 <description>
5770 On return, points to the variable's value.
5771 </description>
5772 </param>
5773 </parameters>
5774 <errors>
5775 <error id="JVMTI_ERROR_INVALID_SLOT">
5776 Invalid <code>slot</code>.
5777 </error>
5778 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5779 The variable type is not <code>long</code>.
5780 </error>
5781 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5782 Not a visible frame
5783 </error>
5784 </errors>
5785 </function>
5787 <function id="GetLocalFloat" num="24">
5788 <synopsis>Get Local Variable - Float</synopsis>
5789 <description>
5790 This function can be used to retrieve the value of a local
5791 variable whose type is <code>float</code>.
5792 </description>
5793 <origin>jvmdi</origin>
5794 <capabilities>
5795 <required id="can_access_local_variables"></required>
5796 </capabilities>
5797 <parameters>
5798 <param id="thread">
5799 <jthread null="current" frame="frame"/>
5800 <description>
5801 The thread of the frame containing the variable's value.
5802 </description>
5803 </param>
5804 <param id="depth">
5805 <jframeID thread="thread"/>
5806 <description>
5807 The depth of the frame containing the variable's value.
5808 </description>
5809 </param>
5810 <param id="slot">
5811 <jint/>
5812 <description>
5813 The variable's slot number.
5814 </description>
5815 </param>
5816 <param id="value_ptr">
5817 <outptr><jfloat/></outptr>
5818 <description>
5819 On return, points to the variable's value.
5820 </description>
5821 </param>
5822 </parameters>
5823 <errors>
5824 <error id="JVMTI_ERROR_INVALID_SLOT">
5825 Invalid <code>slot</code>.
5826 </error>
5827 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5828 The variable type is not <code>float</code>.
5829 </error>
5830 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5831 Not a visible frame
5832 </error>
5833 </errors>
5834 </function>
5836 <function id="GetLocalDouble" num="25">
5837 <synopsis>Get Local Variable - Double</synopsis>
5838 <description>
5839 This function can be used to retrieve the value of a local
5840 variable whose type is <code>long</code>.
5841 </description>
5842 <origin>jvmdi</origin>
5843 <capabilities>
5844 <required id="can_access_local_variables"></required>
5845 </capabilities>
5846 <parameters>
5847 <param id="thread">
5848 <jthread null="current" frame="frame"/>
5849 <description>
5850 The thread of the frame containing the variable's value.
5851 </description>
5852 </param>
5853 <param id="depth">
5854 <jframeID thread="thread"/>
5855 <description>
5856 The depth of the frame containing the variable's value.
5857 </description>
5858 </param>
5859 <param id="slot">
5860 <jint/>
5861 <description>
5862 The variable's slot number.
5863 </description>
5864 </param>
5865 <param id="value_ptr">
5866 <outptr><jdouble/></outptr>
5867 <description>
5868 On return, points to the variable's value.
5869 </description>
5870 </param>
5871 </parameters>
5872 <errors>
5873 <error id="JVMTI_ERROR_INVALID_SLOT">
5874 Invalid <code>slot</code>.
5875 </error>
5876 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5877 The variable type is not <code>double</code>.
5878 </error>
5879 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5880 Not a visible frame
5881 </error>
5882 </errors>
5883 </function>
5885 <function id="SetLocalObject" num="26">
5886 <synopsis>Set Local Variable - Object</synopsis>
5887 <description>
5888 This function can be used to set the value of a local
5889 variable whose type is <code>Object</code> or a subclass of <code>Object</code>.
5890 </description>
5891 <origin>jvmdi</origin>
5892 <capabilities>
5893 <required id="can_access_local_variables"></required>
5894 </capabilities>
5895 <parameters>
5896 <param id="thread">
5897 <jthread null="current" frame="frame"/>
5898 <description>
5899 The thread of the frame containing the variable's value.
5900 </description>
5901 </param>
5902 <param id="depth">
5903 <jframeID thread="thread"/>
5904 <description>
5905 The depth of the frame containing the variable's value.
5906 </description>
5907 </param>
5908 <param id="slot">
5909 <jint/>
5910 <description>
5911 The variable's slot number.
5912 </description>
5913 </param>
5914 <param id="value">
5915 <jobject/>
5916 <description>
5917 The new value for the variable.
5918 </description>
5919 </param>
5920 </parameters>
5921 <errors>
5922 <error id="JVMTI_ERROR_INVALID_SLOT">
5923 Invalid <code>slot</code>.
5924 </error>
5925 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5926 The variable type is not
5927 <code>Object</code> or a subclass of <code>Object</code>.
5928 </error>
5929 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5930 The supplied <paramlink id="value"/> is not compatible
5931 with the variable type.
5932 </error>
5933 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5934 Not a visible frame
5935 </error>
5936 </errors>
5937 </function>
5939 <function id="SetLocalInt" num="27">
5940 <synopsis>Set Local Variable - Int</synopsis>
5941 <description>
5942 This function can be used to set the value of a local
5943 variable whose type is <code>int</code>,
5944 <code>short</code>, <code>char</code>, <code>byte</code>, or
5945 <code>boolean</code>.
5946 </description>
5947 <origin>jvmdi</origin>
5948 <capabilities>
5949 <required id="can_access_local_variables"></required>
5950 </capabilities>
5951 <parameters>
5952 <param id="thread">
5953 <jthread null="current" frame="frame"/>
5954 <description>
5955 The thread of the frame containing the variable's value.
5956 </description>
5957 </param>
5958 <param id="depth">
5959 <jframeID thread="thread"/>
5960 <description>
5961 The depth of the frame containing the variable's value.
5962 </description>
5963 </param>
5964 <param id="slot">
5965 <jint/>
5966 <description>
5967 The variable's slot number.
5968 </description>
5969 </param>
5970 <param id="value">
5971 <jint/>
5972 <description>
5973 The new value for the variable.
5974 </description>
5975 </param>
5976 </parameters>
5977 <errors>
5978 <error id="JVMTI_ERROR_INVALID_SLOT">
5979 Invalid <code>slot</code>.
5980 </error>
5981 <error id="JVMTI_ERROR_TYPE_MISMATCH">
5982 The variable type is not
5983 <code>int</code>, <code>short</code>,
5984 <code>char</code>, <code>byte</code>, or
5985 <code>boolean</code>.
5986 </error>
5987 <error id="JVMTI_ERROR_OPAQUE_FRAME">
5988 Not a visible frame
5989 </error>
5990 </errors>
5991 </function>
5993 <function id="SetLocalLong" num="28">
5994 <synopsis>Set Local Variable - Long</synopsis>
5995 <description>
5996 This function can be used to set the value of a local
5997 variable whose type is <code>long</code>.
5998 </description>
5999 <origin>jvmdi</origin>
6000 <capabilities>
6001 <required id="can_access_local_variables"></required>
6002 </capabilities>
6003 <parameters>
6004 <param id="thread">
6005 <jthread null="current" frame="frame"/>
6006 <description>
6007 The thread of the frame containing the variable's value.
6008 </description>
6009 </param>
6010 <param id="depth">
6011 <jframeID thread="thread"/>
6012 <description>
6013 The depth of the frame containing the variable's value.
6014 </description>
6015 </param>
6016 <param id="slot">
6017 <jint/>
6018 <description>
6019 The variable's slot number.
6020 </description>
6021 </param>
6022 <param id="value">
6023 <jlong/>
6024 <description>
6025 The new value for the variable.
6026 </description>
6027 </param>
6028 </parameters>
6029 <errors>
6030 <error id="JVMTI_ERROR_INVALID_SLOT">
6031 Invalid <code>slot</code>.
6032 </error>
6033 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6034 The variable type is not <code>long</code>.
6035 </error>
6036 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6037 Not a visible frame
6038 </error>
6039 </errors>
6040 </function>
6042 <function id="SetLocalFloat" num="29">
6043 <synopsis>Set Local Variable - Float</synopsis>
6044 <description>
6045 This function can be used to set the value of a local
6046 variable whose type is <code>float</code>.
6047 </description>
6048 <origin>jvmdi</origin>
6049 <capabilities>
6050 <required id="can_access_local_variables"></required>
6051 </capabilities>
6052 <parameters>
6053 <param id="thread">
6054 <jthread null="current" frame="frame"/>
6055 <description>
6056 The thread of the frame containing the variable's value.
6057 </description>
6058 </param>
6059 <param id="depth">
6060 <jframeID thread="thread"/>
6061 <description>
6062 The depth of the frame containing the variable's value.
6063 </description>
6064 </param>
6065 <param id="slot">
6066 <jint/>
6067 <description>
6068 The variable's slot number.
6069 </description>
6070 </param>
6071 <param id="value">
6072 <jfloat/>
6073 <description>
6074 The new value for the variable.
6075 </description>
6076 </param>
6077 </parameters>
6078 <errors>
6079 <error id="JVMTI_ERROR_INVALID_SLOT">
6080 Invalid <code>slot</code>.
6081 </error>
6082 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6083 The variable type is not <code>float</code>.
6084 </error>
6085 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6086 Not a visible frame
6087 </error>
6088 </errors>
6089 </function>
6091 <function id="SetLocalDouble" num="30">
6092 <synopsis>Set Local Variable - Double</synopsis>
6093 <description>
6094 This function can be used to set the value of a local
6095 variable whose type is <code>double</code>.
6096 </description>
6097 <origin>jvmdi</origin>
6098 <capabilities>
6099 <required id="can_access_local_variables"></required>
6100 </capabilities>
6101 <parameters>
6102 <param id="thread">
6103 <jthread null="current" frame="frame"/>
6104 <description>
6105 The thread of the frame containing the variable's value.
6106 </description>
6107 </param>
6108 <param id="depth">
6109 <jframeID thread="thread"/>
6110 <description>
6111 The depth of the frame containing the variable's value.
6112 </description>
6113 </param>
6114 <param id="slot">
6115 <jint/>
6116 <description>
6117 The variable's slot number.
6118 </description>
6119 </param>
6120 <param id="value">
6121 <jdouble/>
6122 <description>
6123 The new value for the variable.
6124 </description>
6125 </param>
6126 </parameters>
6127 <errors>
6128 <error id="JVMTI_ERROR_INVALID_SLOT">
6129 Invalid <code>slot</code>.
6130 </error>
6131 <error id="JVMTI_ERROR_TYPE_MISMATCH">
6132 The variable type is not <code>double</code>.
6133 </error>
6134 <error id="JVMTI_ERROR_OPAQUE_FRAME">
6135 Not a visible frame
6136 </error>
6137 </errors>
6138 </function>
6139 </category>
6141 <category id="breakpointCategory" label="Breakpoint">
6143 <intro>
6144 </intro>
6146 <function id="SetBreakpoint" num="38">
6147 <synopsis>Set Breakpoint</synopsis>
6148 <description>
6149 Set a breakpoint at the instruction indicated by
6150 <code>method</code> and <code>location</code>.
6151 An instruction can only have one breakpoint.
6152 <p/>
6153 Whenever the designated instruction is about to be executed, a
6154 <eventlink id="Breakpoint"></eventlink> event is generated.
6155 </description>
6156 <origin>jvmdi</origin>
6157 <capabilities>
6158 <required id="can_generate_breakpoint_events"></required>
6159 </capabilities>
6160 <parameters>
6161 <param id="klass">
6162 <jclass method="method"/>
6163 <description>
6164 The class in which to set the breakpoint
6165 </description>
6166 </param>
6167 <param id="method">
6168 <jmethodID class="klass"/>
6169 <description>
6170 The method in which to set the breakpoint
6171 </description>
6172 </param>
6173 <param id="location">
6174 <jlocation/>
6175 <description>
6176 the index of the instruction at which to set the breakpoint
6178 </description>
6179 </param>
6180 </parameters>
6181 <errors>
6182 <error id="JVMTI_ERROR_DUPLICATE">
6183 The designated bytecode already has a breakpoint.
6184 </error>
6185 </errors>
6186 </function>
6188 <function id="ClearBreakpoint" num="39">
6189 <synopsis>Clear Breakpoint</synopsis>
6190 <description>
6191 Clear the breakpoint at the bytecode indicated by
6192 <code>method</code> and <code>location</code>.
6193 </description>
6194 <origin>jvmdi</origin>
6195 <capabilities>
6196 <required id="can_generate_breakpoint_events"></required>
6197 </capabilities>
6198 <parameters>
6199 <param id="klass">
6200 <jclass method="method"/>
6201 <description>
6202 The class in which to clear the breakpoint
6203 </description>
6204 </param>
6205 <param id="method">
6206 <jmethodID class="klass"/>
6207 <description>
6208 The method in which to clear the breakpoint
6209 </description>
6210 </param>
6211 <param id="location">
6212 <jlocation/>
6213 <description>
6214 the index of the instruction at which to clear the breakpoint
6215 </description>
6216 </param>
6217 </parameters>
6218 <errors>
6219 <error id="JVMTI_ERROR_NOT_FOUND">
6220 There's no breakpoint at the designated bytecode.
6221 </error>
6222 </errors>
6223 </function>
6225 </category>
6227 <category id="fieldWatch" label="Watched Field">
6229 <intro>
6230 </intro>
6232 <function id="SetFieldAccessWatch" num="41">
6233 <synopsis>Set Field Access Watch</synopsis>
6234 <description>
6235 Generate a <eventlink id="FieldAccess"></eventlink> event
6236 when the field specified
6237 by <code>klass</code> and
6238 <code>field</code> is about to be accessed.
6239 An event will be generated for each access of the field
6240 until it is canceled with
6241 <functionlink id="ClearFieldAccessWatch"></functionlink>.
6242 Field accesses from Java programming language code or from JNI code are watched,
6243 fields modified by other means are not watched.
6244 Note that <jvmti/> users should be aware that their own field accesses
6245 will trigger the watch.
6246 A field can only have one field access watch set.
6247 Modification of a field is not considered an access--use
6248 <functionlink id="SetFieldModificationWatch"></functionlink>
6249 to monitor modifications.
6250 </description>
6251 <origin>jvmdi</origin>
6252 <capabilities>
6253 <required id="can_generate_field_access_events"></required>
6254 </capabilities>
6255 <parameters>
6256 <param id="klass">
6257 <jclass field="field"/>
6258 <description>
6259 The class containing the field to watch
6260 </description>
6261 </param>
6262 <param id="field">
6263 <jfieldID class="klass"/>
6264 <description>
6265 The field to watch
6267 </description>
6268 </param>
6269 </parameters>
6270 <errors>
6271 <error id="JVMTI_ERROR_DUPLICATE">
6272 The designated field is already being watched for accesses.
6273 </error>
6274 </errors>
6275 </function>
6277 <function id="ClearFieldAccessWatch" num="42">
6278 <synopsis>Clear Field Access Watch</synopsis>
6279 <description>
6280 Cancel a field access watch previously set by
6281 <functionlink id="SetFieldAccessWatch"></functionlink>, on the
6282 field specified
6283 by <code>klass</code> and
6284 <code>field</code>.
6285 </description>
6286 <origin>jvmdi</origin>
6287 <capabilities>
6288 <required id="can_generate_field_access_events"></required>
6289 </capabilities>
6290 <parameters>
6291 <param id="klass">
6292 <jclass field="field"/>
6293 <description>
6294 The class containing the field to watch
6295 </description>
6296 </param>
6297 <param id="field">
6298 <jfieldID class="klass"/>
6299 <description>
6300 The field to watch
6302 </description>
6303 </param>
6304 </parameters>
6305 <errors>
6306 <error id="JVMTI_ERROR_NOT_FOUND">
6307 The designated field is not being watched for accesses.
6308 </error>
6309 </errors>
6310 </function>
6312 <function id="SetFieldModificationWatch" num="43">
6313 <synopsis>Set Field Modification Watch</synopsis>
6314 <description>
6315 Generate a <eventlink id="FieldModification"></eventlink> event
6316 when the field specified
6317 by <code>klass</code> and
6318 <code>field</code> is about to be modified.
6319 An event will be generated for each modification of the field
6320 until it is canceled with
6321 <functionlink id="ClearFieldModificationWatch"></functionlink>.
6322 Field modifications from Java programming language code or from JNI code are watched,
6323 fields modified by other means are not watched.
6324 Note that <jvmti/> users should be aware that their own field modifications
6325 will trigger the watch.
6326 A field can only have one field modification watch set.
6327 </description>
6328 <origin>jvmdi</origin>
6329 <capabilities>
6330 <required id="can_generate_field_modification_events"></required>
6331 </capabilities>
6332 <parameters>
6333 <param id="klass">
6334 <jclass field="field"/>
6335 <description>
6336 The class containing the field to watch
6337 </description>
6338 </param>
6339 <param id="field">
6340 <jfieldID class="klass"/>
6341 <description>
6342 The field to watch
6344 </description>
6345 </param>
6346 </parameters>
6347 <errors>
6348 <error id="JVMTI_ERROR_DUPLICATE">
6349 The designated field is already being watched for modifications.
6350 </error>
6351 </errors>
6352 </function>
6354 <function id="ClearFieldModificationWatch" num="44">
6355 <synopsis>Clear Field Modification Watch</synopsis>
6356 <description>
6358 Cancel a field modification watch previously set by
6359 <functionlink id="SetFieldModificationWatch"></functionlink>, on the
6360 field specified
6361 by <code>klass</code> and
6362 <code>field</code>.
6363 </description>
6364 <origin>jvmdi</origin>
6365 <capabilities>
6366 <required id="can_generate_field_modification_events"></required>
6367 </capabilities>
6368 <parameters>
6369 <param id="klass">
6370 <jclass field="field"/>
6371 <description>
6372 The class containing the field to watch
6373 </description>
6374 </param>
6375 <param id="field">
6376 <jfieldID class="klass"/>
6377 <description>
6378 The field to watch
6380 </description>
6381 </param>
6382 </parameters>
6383 <errors>
6384 <error id="JVMTI_ERROR_NOT_FOUND">
6385 The designated field is not being watched for modifications.
6386 </error>
6387 </errors>
6388 </function>
6389 </category>
6391 <category id="class" label="Class">
6393 <intro>
6394 </intro>
6396 <function id="GetLoadedClasses" jkernel="yes" num="78">
6397 <synopsis>Get Loaded Classes</synopsis>
6398 <description>
6399 Return an array of all classes loaded in the virtual machine.
6400 The number of classes in the array is returned via
6401 <code>class_count_ptr</code>, and the array itself via
6402 <code>classes_ptr</code>.
6403 <p/>
6404 Array classes of all types (including arrays of primitive types) are
6405 included in the returned list. Primitive classes (for example,
6406 <code>java.lang.Integer.TYPE</code>) are <i>not</i> included in this list.
6407 </description>
6408 <origin>jvmdi</origin>
6409 <capabilities>
6410 </capabilities>
6411 <parameters>
6412 <param id="class_count_ptr">
6413 <outptr><jint/></outptr>
6414 <description>
6415 On return, points to the number of classes.
6416 </description>
6417 </param>
6418 <param id="classes_ptr">
6419 <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6420 <description>
6421 On return, points to an array of references, one
6422 for each class.
6423 </description>
6424 </param>
6425 </parameters>
6426 <errors>
6427 </errors>
6428 </function>
6430 <function id="GetClassLoaderClasses" jkernel="yes" num="79">
6431 <synopsis>Get Classloader Classes</synopsis>
6432 <description>
6433 Returns an array of those classes for which this class loader has
6434 been recorded as an initiating loader. Each
6435 class in the returned array was created by this class loader,
6436 either by defining it directly or by delegation to another class loader.
6437 See <vmspec chapter="5.3"/>.
6438 <p/>
6439 For JDK version 1.1 implementations that don't
6440 recognize the distinction between initiating and defining class loaders,
6441 this function should return all classes loaded in the virtual machine.
6442 The number of classes in the array is returned via
6443 <code>class_count_ptr</code>, and the array itself via
6444 <code>classes_ptr</code>.
6445 </description>
6446 <origin>jvmdi</origin>
6447 <capabilities>
6448 </capabilities>
6449 <parameters>
6450 <param id="initiating_loader">
6451 <ptrtype>
6452 <jobject/>
6453 <nullok>the classes initiated by the bootstrap loader will be returned</nullok>
6454 </ptrtype>
6455 <description>
6456 An initiating class loader.
6457 </description>
6458 </param>
6459 <param id="class_count_ptr">
6460 <outptr><jint/></outptr>
6461 <description>
6462 On return, points to the number of classes.
6463 </description>
6464 </param>
6465 <param id="classes_ptr">
6466 <allocbuf outcount="class_count_ptr"><jclass/></allocbuf>
6467 <description>
6468 On return, points to an array of references, one
6469 for each class.
6470 </description>
6471 </param>
6472 </parameters>
6473 <errors>
6474 </errors>
6475 </function>
6477 <function id="GetClassSignature" phase="start" num="48">
6478 <synopsis>Get Class Signature</synopsis>
6479 <description>
6480 For the class indicated by <code>klass</code>, return the
6481 <externallink id="http://java.sun.com/javase/6/docs/guide/jni/spec/types.html#wp16432">JNI
6482 type signature</externallink>
6483 and the generic signature of the class.
6484 For example, <code>java.util.List</code> is <code>"Ljava/util/List;"</code>
6485 and <code>int[]</code> is <code>"[I"</code>
6486 The returned name for primitive classes
6487 is the type signature character of the corresponding primitive type.
6488 For example, <code>java.lang.Integer.TYPE</code> is <code>"I"</code>.
6489 </description>
6490 <origin>jvmdiClone</origin>
6491 <capabilities>
6492 </capabilities>
6493 <parameters>
6494 <param id="klass">
6495 <jclass/>
6496 <description>
6497 The class to query.
6498 </description>
6499 </param>
6500 <param id="signature_ptr">
6501 <allocbuf>
6502 <char/>
6503 <nullok>the signature is not returned</nullok>
6504 </allocbuf>
6505 <description>
6506 On return, points to the JNI type signature of the class, encoded as a
6507 <internallink id="mUTF">modified UTF-8</internallink> string.
6508 </description>
6509 </param>
6510 <param id="generic_ptr">
6511 <allocbuf>
6512 <char/>
6513 <nullok>the generic signature is not returned</nullok>
6514 </allocbuf>
6515 <description>
6516 On return, points to the generic signature of the class, encoded as a
6517 <internallink id="mUTF">modified UTF-8</internallink> string.
6518 If there is no generic signature attribute for the class, then,
6519 on return, points to <code>NULL</code>.
6520 </description>
6521 </param>
6522 </parameters>
6523 <errors>
6524 </errors>
6525 </function>
6527 <function id="GetClassStatus" phase="start" num="49">
6528 <synopsis>Get Class Status</synopsis>
6529 <description>
6530 Get the status of the class. Zero or more of the following bits can be
6531 set.
6532 <constants id="jvmtiClassStatus" label="Class Status Flags" kind="bits">
6533 <constant id="JVMTI_CLASS_STATUS_VERIFIED" num="1">
6534 Class bytecodes have been verified
6535 </constant>
6536 <constant id="JVMTI_CLASS_STATUS_PREPARED" num="2">
6537 Class preparation is complete
6538 </constant>
6539 <constant id="JVMTI_CLASS_STATUS_INITIALIZED" num="4">
6540 Class initialization is complete. Static initializer has been run.
6541 </constant>
6542 <constant id="JVMTI_CLASS_STATUS_ERROR" num="8">
6543 Error during initialization makes class unusable
6544 </constant>
6545 <constant id="JVMTI_CLASS_STATUS_ARRAY" num="16">
6546 Class is an array. If set, all other bits are zero.
6547 </constant>
6548 <constant id="JVMTI_CLASS_STATUS_PRIMITIVE" num="32">
6549 Class is a primitive class (for example, <code>java.lang.Integer.TYPE</code>).
6550 If set, all other bits are zero.
6551 </constant>
6552 </constants>
6553 </description>
6554 <origin>jvmdi</origin>
6555 <capabilities>
6556 </capabilities>
6557 <parameters>
6558 <param id="klass">
6559 <jclass/>
6560 <description>
6561 The class to query.
6562 </description>
6563 </param>
6564 <param id="status_ptr">
6565 <outptr><jint/></outptr>
6566 <description>
6567 On return, points to the current state of this class as one or
6568 more of the <internallink id="jvmtiClassStatus">class status flags</internallink>.
6569 </description>
6570 </param>
6571 </parameters>
6572 <errors>
6573 </errors>
6574 </function>
6576 <function id="GetSourceFileName" phase="start" num="50">
6577 <synopsis>Get Source File Name</synopsis>
6578 <description>
6579 For the class indicated by <code>klass</code>, return the source file
6580 name via <code>source_name_ptr</code>. The returned string
6581 is a file name only and never contains a directory name.
6582 <p/>
6583 For primitive classes (for example, <code>java.lang.Integer.TYPE</code>)
6584 and for arrays this function returns
6585 <errorlink id="JVMTI_ERROR_ABSENT_INFORMATION"></errorlink>.
6586 </description>
6587 <origin>jvmdi</origin>
6588 <capabilities>
6589 <required id="can_get_source_file_name"></required>
6590 </capabilities>
6591 <parameters>
6592 <param id="klass">
6593 <jclass/>
6594 <description>
6595 The class to query.
6596 </description>
6597 </param>
6598 <param id="source_name_ptr">
6599 <allocbuf><char/></allocbuf>
6600 <description>
6601 On return, points to the class's source file name, encoded as a
6602 <internallink id="mUTF">modified UTF-8</internallink> string.
6603 </description>
6604 </param>
6605 </parameters>
6606 <errors>
6607 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
6608 Class information does not include a source file name. This includes
6609 cases where the class is an array class or primitive class.
6610 </error>
6611 </errors>
6612 </function>
6614 <function id="GetClassModifiers" phase="start" num="51">
6615 <synopsis>Get Class Modifiers</synopsis>
6616 <description>
6617 For the class indicated by <code>klass</code>, return the access
6618 flags
6619 via <code>modifiers_ptr</code>.
6620 Access flags are defined in <vmspec chapter="4"/>.
6621 <p/>
6622 If the class is an array class, then its public, private, and protected
6623 modifiers are the same as those of its component type. For arrays of
6624 primitives, this component type is represented by one of the primitive
6625 classes (for example, <code>java.lang.Integer.TYPE</code>).
6626 <p/>
6627 If the class is a primitive class, its public modifier is always true,
6628 and its protected and private modifiers are always false.
6629 <p/>
6630 If the class is an array class or a primitive class then its final
6631 modifier is always true and its interface modifier is always false.
6632 The values of its other modifiers are not determined by this specification.
6634 </description>
6635 <origin>jvmdi</origin>
6636 <capabilities>
6637 </capabilities>
6638 <parameters>
6639 <param id="klass">
6640 <jclass/>
6641 <description>
6642 The class to query.
6643 </description>
6644 </param>
6645 <param id="modifiers_ptr">
6646 <outptr><jint/></outptr>
6647 <description>
6648 On return, points to the current access flags of this class.
6650 </description>
6651 </param>
6652 </parameters>
6653 <errors>
6654 </errors>
6655 </function>
6657 <function id="GetClassMethods" phase="start" num="52">
6658 <synopsis>Get Class Methods</synopsis>
6659 <description>
6660 For the class indicated by <code>klass</code>, return a count of
6661 methods via <code>method_count_ptr</code> and a list of
6662 method IDs via <code>methods_ptr</code>. The method list contains
6663 constructors and static initializers as well as true methods.
6664 Only directly declared methods are returned (not inherited methods).
6665 An empty method list is returned for array classes and primitive classes
6666 (for example, <code>java.lang.Integer.TYPE</code>).
6667 </description>
6668 <origin>jvmdi</origin>
6669 <capabilities>
6670 <capability id="can_maintain_original_method_order"/>
6671 </capabilities>
6672 <parameters>
6673 <param id="klass">
6674 <jclass/>
6675 <description>
6676 The class to query.
6677 </description>
6678 </param>
6679 <param id="method_count_ptr">
6680 <outptr><jint/></outptr>
6681 <description>
6682 On return, points to the number of methods declared in this class.
6683 </description>
6684 </param>
6685 <param id="methods_ptr">
6686 <allocbuf outcount="method_count_ptr"><jmethodID class="klass"/></allocbuf>
6687 <description>
6688 On return, points to the method ID array.
6689 </description>
6690 </param>
6691 </parameters>
6692 <errors>
6693 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
6694 <paramlink id="klass"></paramlink> is not prepared.
6695 </error>
6696 </errors>
6697 </function>
6699 <function id="GetClassFields" phase="start" num="53">
6700 <synopsis>Get Class Fields</synopsis>
6701 <description>
6702 For the class indicated by <code>klass</code>, return a count of fields
6703 via <code>field_count_ptr</code> and a list of field IDs via
6704 <code>fields_ptr</code>.
6705 Only directly declared fields are returned (not inherited fields).
6706 Fields are returned in the order they occur in the class file.
6707 An empty field list is returned for array classes and primitive classes
6708 (for example, <code>java.lang.Integer.TYPE</code>).
6709 Use JNI to determine the length of an array.
6710 </description>
6711 <origin>jvmdi</origin>
6712 <capabilities>
6713 </capabilities>
6714 <parameters>
6715 <param id="klass">
6716 <jclass/>
6717 <description>
6718 The class to query.
6719 </description>
6720 </param>
6721 <param id="field_count_ptr">
6722 <outptr><jint/></outptr>
6723 <description>
6724 On return, points to the number of fields declared in this class.
6725 </description>
6726 </param>
6727 <param id="fields_ptr">
6728 <allocbuf outcount="field_count_ptr"><jfieldID/></allocbuf>
6729 <description>
6730 On return, points to the field ID array.
6731 </description>
6732 </param>
6733 </parameters>
6734 <errors>
6735 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
6736 <paramlink id="klass"></paramlink> is not prepared.
6737 </error>
6738 </errors>
6739 </function>
6741 <function id="GetImplementedInterfaces" phase="start" num="54">
6742 <synopsis>Get Implemented Interfaces</synopsis>
6743 <description>
6744 Return the direct super-interfaces of this class. For a class, this
6745 function returns the interfaces declared in its <code>implements</code>
6746 clause. For an interface, this function returns the interfaces declared in
6747 its <code>extends</code> clause.
6748 An empty interface list is returned for array classes and primitive classes
6749 (for example, <code>java.lang.Integer.TYPE</code>).
6750 </description>
6751 <origin>jvmdi</origin>
6752 <capabilities>
6753 </capabilities>
6754 <parameters>
6755 <param id="klass">
6756 <jclass/>
6757 <description>
6758 The class to query.
6759 </description>
6760 </param>
6761 <param id="interface_count_ptr">
6762 <outptr><jint/></outptr>
6763 <description>
6764 On return, points to the number of interfaces.
6765 </description>
6766 </param>
6767 <param id="interfaces_ptr">
6768 <allocbuf outcount="interface_count_ptr"><jclass/></allocbuf>
6769 <description>
6770 On return, points to the interface array.
6771 </description>
6772 </param>
6773 </parameters>
6774 <errors>
6775 <error id="JVMTI_ERROR_CLASS_NOT_PREPARED">
6776 <paramlink id="klass"></paramlink> is not prepared.
6777 </error>
6778 </errors>
6779 </function>
6781 <function id="GetClassVersionNumbers" phase="start" num="145" since="1.1">
6782 <synopsis>Get Class Version Numbers</synopsis>
6783 <description>
6784 For the class indicated by <code>klass</code>,
6785 return the minor and major version numbers,
6786 as defined in
6787 <vmspec chapter="4"/>.
6788 </description>
6789 <origin>new</origin>
6790 <capabilities>
6791 </capabilities>
6792 <parameters>
6793 <param id="klass">
6794 <jclass/>
6795 <description>
6796 The class to query.
6797 </description>
6798 </param>
6799 <param id="minor_version_ptr">
6800 <outptr><jint/></outptr>
6801 <description>
6802 On return, points to the value of the
6803 <code>minor_version</code> item of the
6804 Class File Format.
6805 Note: to be consistent with the Class File Format,
6806 the minor version number is the first parameter.
6807 </description>
6808 </param>
6809 <param id="major_version_ptr">
6810 <outptr><jint/></outptr>
6811 <description>
6812 On return, points to the value of the
6813 <code>major_version</code> item of the
6814 Class File Format.
6815 </description>
6816 </param>
6817 </parameters>
6818 <errors>
6819 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
6820 The class is a primitive or array class.
6821 </error>
6822 </errors>
6823 </function>
6825 <function id="GetConstantPool" phase="start" num="146" since="1.1">
6826 <synopsis>Get Constant Pool</synopsis>
6827 <description>
6828 For the class indicated by <code>klass</code>,
6829 return the raw bytes of the constant pool in the format of the
6830 <code>constant_pool</code> item of
6831 <vmspec chapter="4"/>.
6832 The format of the constant pool may differ between versions
6833 of the Class File Format, so, the
6834 <functionlink id="GetClassVersionNumbers">minor and major
6835 class version numbers</functionlink> should be checked for
6836 compatibility.
6837 <p/>
6838 The returned constant pool might not have the same layout or
6839 contents as the constant pool in the defining class file.
6840 The constant pool returned by GetConstantPool() may have
6841 more or fewer entries than the defining constant pool.
6842 Entries may be in a different order.
6843 The constant pool returned by GetConstantPool() will match the
6844 constant pool used by
6845 <functionlink id="GetBytecodes">GetBytecodes()</functionlink>.
6846 That is, the bytecodes returned by GetBytecodes() will have
6847 constant pool indices which refer to constant pool entries returned
6848 by GetConstantPool().
6849 Note that since <functionlink id="RetransformClasses"/>
6850 and <functionlink id="RedefineClasses"/> can change
6851 the constant pool, the constant pool returned by this function
6852 can change accordingly. Thus, the correspondence between
6853 GetConstantPool() and GetBytecodes() does not hold if there
6854 is an intervening class retransformation or redefinition.
6855 The value of a constant pool entry used by a given bytecode will
6856 match that of the defining class file (even if the indices don't match).
6857 Constant pool entries which are not used directly or indirectly by
6858 bytecodes (for example, UTF-8 strings associated with annotations) are
6859 not required to exist in the returned constant pool.
6860 </description>
6861 <origin>new</origin>
6862 <capabilities>
6863 <required id="can_get_constant_pool"></required>
6864 </capabilities>
6865 <parameters>
6866 <param id="klass">
6867 <jclass/>
6868 <description>
6869 The class to query.
6870 </description>
6871 </param>
6872 <param id="constant_pool_count_ptr">
6873 <outptr><jint/></outptr>
6874 <description>
6875 On return, points to the number of entries
6876 in the constant pool table plus one.
6877 This corresponds to the <code>constant_pool_count</code>
6878 item of the Class File Format.
6879 </description>
6880 </param>
6881 <param id="constant_pool_byte_count_ptr">
6882 <outptr><jint/></outptr>
6883 <description>
6884 On return, points to the number of bytes
6885 in the returned raw constant pool.
6886 </description>
6887 </param>
6888 <param id="constant_pool_bytes_ptr">
6889 <allocbuf outcount="constant_pool_byte_count_ptr"><uchar/></allocbuf>
6890 <description>
6891 On return, points to the raw constant pool, that is the bytes
6892 defined by the <code>constant_pool</code> item of the
6893 Class File Format
6894 </description>
6895 </param>
6896 </parameters>
6897 <errors>
6898 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
6899 The class is a primitive or array class.
6900 </error>
6901 </errors>
6902 </function>
6904 <function id="IsInterface" phase="start" num="55">
6905 <synopsis>Is Interface</synopsis>
6906 <description>
6907 Determines whether a class object reference represents an interface.
6908 The <code>jboolean</code> result is
6909 <code>JNI_TRUE</code> if the "class" is actually an interface,
6910 <code>JNI_FALSE</code> otherwise.
6911 </description>
6912 <origin>jvmdi</origin>
6913 <capabilities>
6914 </capabilities>
6915 <parameters>
6916 <param id="klass">
6917 <jclass/>
6918 <description>
6919 The class to query.
6920 </description>
6921 </param>
6922 <param id="is_interface_ptr">
6923 <outptr><jboolean/></outptr>
6924 <description>
6925 On return, points to the boolean result of this function.
6927 </description>
6928 </param>
6929 </parameters>
6930 <errors>
6931 </errors>
6932 </function>
6934 <function id="IsArrayClass" phase="start" num="56">
6935 <synopsis>Is Array Class</synopsis>
6936 <description>
6937 Determines whether a class object reference represents an array.
6938 The <code>jboolean</code> result is
6939 <code>JNI_TRUE</code> if the class is an array,
6940 <code>JNI_FALSE</code> otherwise.
6941 </description>
6942 <origin>jvmdi</origin>
6943 <capabilities>
6944 </capabilities>
6945 <parameters>
6946 <param id="klass">
6947 <jclass/>
6948 <description>
6949 The class to query.
6950 </description>
6951 </param>
6952 <param id="is_array_class_ptr">
6953 <outptr><jboolean/></outptr>
6954 <description>
6955 On return, points to the boolean result of this function.
6957 </description>
6958 </param>
6959 </parameters>
6960 <errors>
6961 </errors>
6962 </function>
6964 <function id="IsModifiableClass" jkernel="yes" phase="start" num="45" since="1.1">
6965 <synopsis>Is Modifiable Class</synopsis>
6966 <description>
6967 Determines whether a class is modifiable.
6968 If a class is modifiable (<paramlink id="is_modifiable_class_ptr"/>
6969 returns <code>JNI_TRUE</code>) the class can be
6970 redefined with <functionlink id="RedefineClasses"/> (assuming
6971 the agent possesses the
6972 <fieldlink id="can_redefine_classes" struct="jvmtiCapabilities"/>
6973 capability) or
6974 retransformed with <functionlink id="RetransformClasses"/> (assuming
6975 the agent possesses the
6976 <fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
6977 capability).
6978 If a class is not modifiable (<paramlink id="is_modifiable_class_ptr"/>
6979 returns <code>JNI_FALSE</code>) the class can be neither
6980 redefined nor retransformed.
6981 <p/>
6982 Primitive classes (for example, <code>java.lang.Integer.TYPE</code>)
6983 and array classes are never modifiable.
6984 <p/>
6985 </description>
6986 <origin>new</origin>
6987 <capabilities>
6988 <capability id="can_redefine_any_class">
6989 If possessed then all classes (except primitive and array classes)
6990 are modifiable.
6991 </capability>
6992 <capability id="can_redefine_classes">
6993 No effect on the result of the function.
6994 But must additionally be possessed to modify the class with
6995 <functionlink id="RedefineClasses"/>.
6996 </capability>
6997 <capability id="can_retransform_classes">
6998 No effect on the result of the function.
6999 But must additionally be possessed to modify the class with
7000 <functionlink id="RetransformClasses"/>.
7001 </capability>
7002 </capabilities>
7003 <parameters>
7004 <param id="klass">
7005 <jclass/>
7006 <description>
7007 The class to query.
7008 </description>
7009 </param>
7010 <param id="is_modifiable_class_ptr">
7011 <outptr><jboolean/></outptr>
7012 <description>
7013 On return, points to the boolean result of this function.
7014 </description>
7015 </param>
7016 </parameters>
7017 <errors>
7018 </errors>
7019 </function>
7021 <function id="GetClassLoader" phase="start" num="57">
7022 <synopsis>Get Class Loader</synopsis>
7023 <description>
7024 For the class indicated by <code>klass</code>, return via
7025 <code>classloader_ptr</code> a reference to the class loader for the
7026 class.
7027 </description>
7028 <origin>jvmdi</origin>
7029 <capabilities>
7030 </capabilities>
7031 <parameters>
7032 <param id="klass">
7033 <jclass/>
7034 <description>
7035 The class to query.
7036 </description>
7037 </param>
7038 <param id="classloader_ptr">
7039 <outptr><jobject/></outptr>
7040 <description>
7041 On return, points to the class loader that loaded
7042 this class.
7043 If the class was not created by a class loader
7044 or if the class loader is the bootstrap class loader,
7045 points to <code>NULL</code>.
7046 </description>
7047 </param>
7048 </parameters>
7049 <errors>
7050 </errors>
7052 </function>
7054 <function id="GetSourceDebugExtension" phase="start" num="90">
7055 <synopsis>Get Source Debug Extension</synopsis>
7056 <description>
7057 For the class indicated by <code>klass</code>, return the debug
7058 extension via <code>source_debug_extension_ptr</code>.
7059 The returned string
7060 contains exactly the debug extension information present in the
7061 class file of <code>klass</code>.
7062 </description>
7063 <origin>jvmdi</origin>
7064 <capabilities>
7065 <required id="can_get_source_debug_extension"></required>
7066 </capabilities>
7067 <parameters>
7068 <param id="klass">
7069 <jclass/>
7070 <description>
7071 The class to query.
7072 </description>
7073 </param>
7074 <param id="source_debug_extension_ptr">
7075 <allocbuf><char/></allocbuf>
7076 <description>
7077 On return, points to the class's debug extension, encoded as a
7078 <internallink id="mUTF">modified UTF-8</internallink> string.
7079 </description>
7080 </param>
7081 </parameters>
7082 <errors>
7083 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
7084 Class information does not include a debug extension.
7085 </error>
7086 </errors>
7087 </function>
7089 <function id="RetransformClasses" jkernel="yes" num="152" since="1.1">
7090 <synopsis>Retransform Classes</synopsis>
7091 <description>
7092 This function facilitates the
7093 <internallink id="bci">bytecode instrumentation</internallink>
7094 of already loaded classes.
7095 To replace the class definition without reference to the existing
7096 bytecodes, as one might do when recompiling from source for
7097 fix-and-continue debugging, <functionlink id="RedefineClasses"/>
7098 function should be used instead.
7099 <p/>
7100 When classes are initially loaded or when they are
7101 <functionlink id="RedefineClasses">redefined</functionlink>,
7102 the initial class file bytes can be transformed with the
7103 <eventlink id="ClassFileLoadHook"/> event.
7104 This function reruns the transformation process
7105 (whether or not a transformation has previously occurred).
7106 This retransformation follows these steps:
7107 <ul>
7108 <li>starting from the initial class file bytes
7109 </li>
7110 <li>for each <fieldlink id="can_retransform_classes"
7111 struct="jvmtiCapabilities">retransformation
7112 incapable</fieldlink>
7113 agent which received a
7114 <code>ClassFileLoadHook</code> event during the previous
7115 load or redefine, the bytes it returned
7116 (via the <code>new_class_data</code> parameter)
7117 are reused as the output of the transformation;
7118 note that this is equivalent to reapplying
7119 the previous transformation, unaltered. except that
7120 the <code>ClassFileLoadHook</code> event
7121 is <b>not</b> sent to these agents
7122 </li>
7123 <li>for each <fieldlink id="can_retransform_classes"
7124 struct="jvmtiCapabilities">retransformation
7125 capable</fieldlink>
7126 agent, the <code>ClassFileLoadHook</code> event is sent,
7127 allowing a new transformation to be applied
7128 </li>
7129 <li>the transformed class file bytes are installed as the new
7130 definition of the class
7131 </li>
7132 </ul>
7133 See the <eventlink id="ClassFileLoadHook"/> event for more details.
7134 <p/>
7135 The initial class file bytes represent the bytes passed to
7136 <code>ClassLoader.defineClass</code>
7137 or <code>RedefineClasses</code> (before any transformations
7138 were applied), however they may not exactly match them.
7139 The constant pool may differ in ways described in
7140 <functionlink id="GetConstantPool"/>.
7141 Constant pool indices in the bytecodes of methods will correspond.
7142 Some attributes may not be present.
7143 Where order is not meaningful, for example the order of methods,
7144 order may not be preserved.
7145 <p/>
7146 Retransformation can cause new versions of methods to be installed.
7147 Old method versions may become
7148 <internallink id="obsoleteMethods">obsolete</internallink>
7149 The new method version will be used on new invokes.
7150 If a method has active stack frames, those active frames continue to
7151 run the bytecodes of the original method version.
7152 <p/>
7153 This function does not cause any initialization except that which
7154 would occur under the customary JVM semantics.
7155 In other words, retransforming a class does not cause its initializers to be
7156 run. The values of static fields will remain as they were
7157 prior to the call.
7158 <p/>
7159 Threads need not be suspended.
7160 <p/>
7161 All breakpoints in the class are cleared.
7162 <p/>
7163 All attributes are updated.
7164 <p/>
7165 Instances of the retransformed class are not affected -- fields retain their
7166 previous values.
7167 <functionlink id="GetTag">Tags</functionlink> on the instances are
7168 also unaffected.
7169 <p/>
7170 In response to this call, no events other than the
7171 <eventlink id="ClassFileLoadHook"/> event
7172 will be sent.
7173 <p/>
7174 The retransformation may change method bodies, the constant pool and attributes.
7175 The retransformation must not add, remove or rename fields or methods, change the
7176 signatures of methods, change modifiers, or change inheritance.
7177 These restrictions may be lifted in future versions.
7178 See the error return description below for information on error codes
7179 returned if an unsupported retransformation is attempted.
7180 The class file bytes are not verified or installed until they have passed
7181 through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7182 returned error code reflects the result of the transformations.
7183 If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7184 none of the classes to be retransformed will have a new definition installed.
7185 When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7186 all of the classes to be retransformed will have their new definitions installed.
7187 </description>
7188 <origin>new</origin>
7189 <capabilities>
7190 <required id="can_retransform_classes"></required>
7191 <capability id="can_retransform_any_class"></capability>
7192 </capabilities>
7193 <parameters>
7194 <param id="class_count">
7195 <jint min="0"/>
7196 <description>
7197 The number of classes to be retransformed.
7198 </description>
7199 </param>
7200 <param id="classes">
7201 <inbuf incount="class_count"><jclass/></inbuf>
7202 <description>
7203 The array of classes to be retransformed.
7204 </description>
7205 </param>
7206 </parameters>
7207 <errors>
7208 <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7209 One of the <paramlink id="classes"/> cannot be modified.
7210 See <functionlink id="IsModifiableClass"/>.
7211 </error>
7212 <error id="JVMTI_ERROR_INVALID_CLASS">
7213 One of the <paramlink id="classes"/> is not a valid class.
7214 </error>
7215 <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7216 A retransformed class file has a version number not supported by this VM.
7217 </error>
7218 <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7219 A retransformed class file is malformed (The VM would return a <code>ClassFormatError</code>).
7220 </error>
7221 <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7222 The retransformed class file definitions would lead to a circular definition
7223 (the VM would return a <code>ClassCircularityError</code>).
7224 </error>
7225 <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7226 The retransformed class file bytes fail verification.
7227 </error>
7228 <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7229 The class name defined in a retransformed class file is
7230 different from the name in the old class object.
7231 </error>
7232 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7233 A retransformed class file would require adding a method.
7234 </error>
7235 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7236 A retransformed class file changes a field.
7237 </error>
7238 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7239 A direct superclass is different for a retransformed class file,
7240 or the set of directly implemented
7241 interfaces is different.
7242 </error>
7243 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7244 A retransformed class file does not declare a method
7245 declared in the old class version.
7246 </error>
7247 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7248 A retransformed class file has different class modifiers.
7249 </error>
7250 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7251 A method in the retransformed class file has different modifiers
7252 than its counterpart in the old class version.
7253 </error>
7254 </errors>
7255 </function>
7257 <function id="RedefineClasses" jkernel="yes" num="87">
7258 <synopsis>Redefine Classes</synopsis>
7259 <typedef id="jvmtiClassDefinition" label="Class redefinition description">
7260 <field id="klass">
7261 <jclass/>
7262 <description>
7263 Class object for this class
7264 </description>
7265 </field>
7266 <field id="class_byte_count">
7267 <jint/>
7268 <description>
7269 Number of bytes defining class (below)
7270 </description>
7271 </field>
7272 <field id="class_bytes">
7273 <inbuf incount="class_byte_count"><uchar/></inbuf>
7274 <description>
7275 Bytes defining class (in <vmspec chapter="4"/>)
7276 </description>
7277 </field>
7278 </typedef>
7279 <description>
7280 All classes given are redefined according to the definitions
7281 supplied.
7282 This function is used to replace the definition of a class
7283 with a new definition, as might be needed in fix-and-continue
7284 debugging.
7285 Where the existing class file bytes are to be transformed, for
7286 example in
7287 <internallink id="bci">bytecode instrumentation</internallink>,
7288 <functionlink id="RetransformClasses"/> should be used.
7289 <p/>
7290 Redefinition can cause new versions of methods to be installed.
7291 Old method versions may become
7292 <internallink id="obsoleteMethods">obsolete</internallink>
7293 The new method version will be used on new invokes.
7294 If a method has active stack frames, those active frames continue to
7295 run the bytecodes of the original method version.
7296 If resetting of stack frames is desired, use
7297 <functionlink id="PopFrame"></functionlink>
7298 to pop frames with obsolete method versions.
7299 <p/>
7300 This function does not cause any initialization except that which
7301 would occur under the customary JVM semantics.
7302 In other words, redefining a class does not cause its initializers to be
7303 run. The values of static fields will remain as they were
7304 prior to the call.
7305 <p/>
7306 Threads need not be suspended.
7307 <p/>
7308 All breakpoints in the class are cleared.
7309 <p/>
7310 All attributes are updated.
7311 <p/>
7312 Instances of the redefined class are not affected -- fields retain their
7313 previous values.
7314 <functionlink id="GetTag">Tags</functionlink> on the instances are
7315 also unaffected.
7316 <p/>
7317 In response to this call, the <jvmti/> event
7318 <eventlink id="ClassFileLoadHook">Class File Load Hook</eventlink>
7319 will be sent (if enabled), but no other <jvmti/> events will be sent.
7320 <p/>
7321 The redefinition may change method bodies, the constant pool and attributes.
7322 The redefinition must not add, remove or rename fields or methods, change the
7323 signatures of methods, change modifiers, or change inheritance.
7324 These restrictions may be lifted in future versions.
7325 See the error return description below for information on error codes
7326 returned if an unsupported redefinition is attempted.
7327 The class file bytes are not verified or installed until they have passed
7328 through the chain of <eventlink id="ClassFileLoadHook"/> events, thus the
7329 returned error code reflects the result of the transformations applied
7330 to the bytes passed into <paramlink id="class_definitions"/>.
7331 If any error code is returned other than <code>JVMTI_ERROR_NONE</code>,
7332 none of the classes to be redefined will have a new definition installed.
7333 When this function returns (with the error code of <code>JVMTI_ERROR_NONE</code>)
7334 all of the classes to be redefined will have their new definitions installed.
7335 </description>
7336 <origin>jvmdi</origin>
7337 <capabilities>
7338 <required id="can_redefine_classes"></required>
7339 <capability id="can_redefine_any_class"></capability>
7340 </capabilities>
7341 <parameters>
7342 <param id="class_count">
7343 <jint min="0"/>
7344 <description>
7345 The number of classes specified in <code>class_definitions</code>
7346 </description>
7347 </param>
7348 <param id="class_definitions">
7349 <inbuf incount="class_count"><struct>jvmtiClassDefinition</struct></inbuf>
7350 <description>
7351 The array of new class definitions
7352 </description>
7353 </param>
7354 </parameters>
7355 <errors>
7356 <error id="JVMTI_ERROR_NULL_POINTER">
7357 One of <code>class_bytes</code> is <code>NULL</code>.
7358 </error>
7359 <error id="JVMTI_ERROR_UNMODIFIABLE_CLASS">
7360 An element of <code>class_definitions</code> cannot be modified.
7361 See <functionlink id="IsModifiableClass"/>.
7362 </error>
7363 <error id="JVMTI_ERROR_INVALID_CLASS">
7364 An element of <code>class_definitions</code> is not a valid class.
7365 </error>
7366 <error id="JVMTI_ERROR_UNSUPPORTED_VERSION">
7367 A new class file has a version number not supported by this VM.
7368 </error>
7369 <error id="JVMTI_ERROR_INVALID_CLASS_FORMAT">
7370 A new class file is malformed (The VM would return a <code>ClassFormatError</code>).
7371 </error>
7372 <error id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION">
7373 The new class file definitions would lead to a circular definition
7374 (the VM would return a <code>ClassCircularityError</code>).
7375 </error>
7376 <error id="JVMTI_ERROR_FAILS_VERIFICATION">
7377 The class bytes fail verification.
7378 </error>
7379 <error id="JVMTI_ERROR_NAMES_DONT_MATCH">
7380 The class name defined in a new class file is
7381 different from the name in the old class object.
7382 </error>
7383 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED">
7384 A new class file would require adding a method.
7385 </error>
7386 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED">
7387 A new class version changes a field.
7388 </error>
7389 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED">
7390 A direct superclass is different for a new class
7391 version, or the set of directly implemented
7392 interfaces is different.
7393 </error>
7394 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED">
7395 A new class version does not declare a method
7396 declared in the old class version.
7397 </error>
7398 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED">
7399 A new class version has different modifiers.
7400 </error>
7401 <error id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED">
7402 A method in the new class version has different modifiers
7403 than its counterpart in the old class version.
7404 </error>
7405 </errors>
7406 </function>
7408 </category>
7410 <category id="object" label="Object">
7412 <function id="GetObjectSize" jkernel="yes" phase="start" num="154">
7413 <synopsis>Get Object Size</synopsis>
7414 <description>
7415 For the object indicated by <code>object</code>,
7416 return via <code>size_ptr</code> the size of the object.
7417 This size is an implementation-specific approximation of
7418 the amount of storage consumed by this object.
7419 It may include some or all of the object's overhead, and thus
7420 is useful for comparison within an implementation but not
7421 between implementations.
7422 The estimate may change during a single invocation of the JVM.
7423 </description>
7424 <origin>new</origin>
7425 <capabilities>
7426 </capabilities>
7427 <parameters>
7428 <param id="object">
7429 <jobject/>
7430 <description>
7431 The object to query.
7432 </description>
7433 </param>
7434 <param id="size_ptr">
7435 <outptr><jlong/></outptr>
7436 <description>
7437 On return, points to the object's size in bytes.
7438 </description>
7439 </param>
7440 </parameters>
7441 <errors>
7442 </errors>
7443 </function>
7445 <function id="GetObjectHashCode" phase="start" num="58">
7446 <synopsis>Get Object Hash Code</synopsis>
7447 <description>
7448 For the object indicated by <code>object</code>,
7449 return via <code>hash_code_ptr</code> a hash code.
7450 This hash code could be used to maintain a hash table of object references,
7451 however, on some implementations this can cause significant performance
7452 impacts--in most cases
7453 <internallink id="Heap">tags</internallink>
7454 will be a more efficient means of associating information with objects.
7455 This function guarantees
7456 the same hash code value for a particular object throughout its life
7457 </description>
7458 <origin>jvmdi</origin>
7459 <capabilities>
7460 </capabilities>
7461 <parameters>
7462 <param id="object">
7463 <jobject/>
7464 <description>
7465 The object to query.
7466 </description>
7467 </param>
7468 <param id="hash_code_ptr">
7469 <outptr><jint/></outptr>
7470 <description>
7471 On return, points to the object's hash code.
7472 </description>
7473 </param>
7474 </parameters>
7475 <errors>
7476 </errors>
7477 </function>
7479 <function id="GetObjectMonitorUsage" num="59">
7480 <synopsis>Get Object Monitor Usage</synopsis>
7481 <typedef id="jvmtiMonitorUsage" label="Object monitor usage information">
7482 <field id="owner">
7483 <jthread/>
7484 <description>
7485 The thread owning this monitor, or <code>NULL</code> if unused
7486 </description>
7487 </field>
7488 <field id="entry_count">
7489 <jint/>
7490 <description>
7491 The number of times the owning thread has entered the monitor
7492 </description>
7493 </field>
7494 <field id="waiter_count">
7495 <jint/>
7496 <description>
7497 The number of threads waiting to own this monitor
7498 </description>
7499 </field>
7500 <field id="waiters">
7501 <allocfieldbuf><jthread/></allocfieldbuf>
7502 <description>
7503 The <code>waiter_count</code> waiting threads
7504 </description>
7505 </field>
7506 <field id="notify_waiter_count">
7507 <jint/>
7508 <description>
7509 The number of threads waiting to be notified by this monitor
7510 </description>
7511 </field>
7512 <field id="notify_waiters">
7513 <allocfieldbuf><jthread/></allocfieldbuf>
7514 <description>
7515 The <code>notify_waiter_count</code> threads waiting to be notified
7516 </description>
7517 </field>
7518 </typedef>
7519 <description>
7520 Get information about the object's monitor.
7521 The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
7522 are filled in with information about usage of the monitor.
7523 <todo>
7524 Decide and then clarify suspend requirements.
7525 </todo>
7526 </description>
7527 <origin>jvmdi</origin>
7528 <capabilities>
7529 <required id="can_get_monitor_info"></required>
7530 </capabilities>
7531 <parameters>
7532 <param id="object">
7533 <jobject/>
7534 <description>
7535 The object to query.
7536 </description>
7537 </param>
7538 <param id="info_ptr">
7539 <outptr><struct>jvmtiMonitorUsage</struct></outptr>
7540 <description>
7541 On return, filled with monitor information for the
7542 specified object.
7543 </description>
7544 </param>
7545 </parameters>
7546 <errors>
7547 </errors>
7548 </function>
7550 <elide>
7551 <function id="GetObjectMonitors" num="116">
7552 <synopsis>Get Object Monitors</synopsis>
7553 <description>
7554 Return the list of object monitors.
7555 <p/>
7556 Note: details about each monitor can be examined with
7557 <functionlink id="GetObjectMonitorUsage"></functionlink>.
7558 </description>
7559 <origin>new</origin>
7560 <capabilities>
7561 <required id="can_get_monitor_info"></required>
7562 </capabilities>
7563 <parameters>
7564 <param id="monitorCnt">
7565 <outptr><jint/></outptr>
7566 <description>
7567 On return, pointer to the number
7568 of monitors returned in <code>monitors_ptr</code>.
7569 </description>
7570 </param>
7571 <param id="monitors_ptr">
7572 <allocbuf outcount="monitorCnt"><jobject/></allocbuf>
7573 <description>
7574 On return, pointer to the monitor list.
7575 </description>
7576 </param>
7577 </parameters>
7578 <errors>
7579 </errors>
7580 </function>
7581 </elide>
7583 </category>
7585 <category id="fieldCategory" label="Field">
7587 <intro>
7588 </intro>
7590 <function id="GetFieldName" phase="start" num="60">
7591 <synopsis>Get Field Name (and Signature)</synopsis>
7592 <description>
7593 For the field indicated by <paramlink id="klass"/> and <paramlink id="field"/>,
7594 return the field name via <paramlink id="name_ptr"/> and field signature via
7595 <paramlink id="signature_ptr"/>.
7596 <p/>
7597 Field signatures are defined in the JNI Specification and
7598 are referred to as <code>field descriptors</code> in
7599 <vmspec chapter="4.3.2"/>.
7600 </description>
7601 <origin>jvmdiClone</origin>
7602 <capabilities>
7603 </capabilities>
7604 <parameters>
7605 <param id="klass">
7606 <jclass field="field"/>
7607 <description>
7608 The class of the field to query.
7609 </description>
7610 </param>
7611 <param id="field">
7612 <jfieldID class="klass"/>
7613 <description>
7614 The field to query.
7615 </description>
7616 </param>
7617 <param id="name_ptr">
7618 <allocbuf>
7619 <char/>
7620 <nullok>the name is not returned</nullok>
7621 </allocbuf>
7622 <description>
7623 On return, points to the field name, encoded as a
7624 <internallink id="mUTF">modified UTF-8</internallink> string.
7625 </description>
7626 </param>
7627 <param id="signature_ptr">
7628 <allocbuf>
7629 <char/>
7630 <nullok>the signature is not returned</nullok>
7631 </allocbuf>
7632 <description>
7633 On return, points to the field signature, encoded as a
7634 <internallink id="mUTF">modified UTF-8</internallink> string.
7635 </description>
7636 </param>
7637 <param id="generic_ptr">
7638 <allocbuf>
7639 <char/>
7640 <nullok>the generic signature is not returned</nullok>
7641 </allocbuf>
7642 <description>
7643 On return, points to the generic signature of the field, encoded as a
7644 <internallink id="mUTF">modified UTF-8</internallink> string.
7645 If there is no generic signature attribute for the field, then,
7646 on return, points to <code>NULL</code>.
7647 </description>
7648 </param>
7649 </parameters>
7650 <errors>
7651 </errors>
7652 </function>
7654 <function id="GetFieldDeclaringClass" phase="start" num="61">
7655 <synopsis>Get Field Declaring Class</synopsis>
7656 <description>
7657 For the field indicated by <code>klass</code> and <code>field</code>
7658 return the class that defined it via <code>declaring_class_ptr</code>.
7659 The declaring class will either be <code>klass</code>, a superclass, or
7660 an implemented interface.
7661 </description>
7662 <origin>jvmdi</origin>
7663 <capabilities>
7664 </capabilities>
7665 <parameters>
7666 <param id="klass">
7667 <jclass field="field"/>
7668 <description>
7669 The class to query.
7670 </description>
7671 </param>
7672 <param id="field">
7673 <jfieldID class="klass"/>
7674 <description>
7675 The field to query.
7676 </description>
7677 </param>
7678 <param id="declaring_class_ptr">
7679 <outptr><jclass/></outptr>
7680 <description>
7681 On return, points to the declaring class
7682 </description>
7683 </param>
7684 </parameters>
7685 <errors>
7686 </errors>
7687 </function>
7689 <function id="GetFieldModifiers" phase="start" num="62">
7690 <synopsis>Get Field Modifiers</synopsis>
7691 <description>
7692 For the field indicated by <code>klass</code> and <code>field</code>
7693 return the access flags via <code>modifiers_ptr</code>.
7694 Access flags are defined in <vmspec chapter="4"/>.
7695 </description>
7696 <origin>jvmdi</origin>
7697 <capabilities>
7698 </capabilities>
7699 <parameters>
7700 <param id="klass">
7701 <jclass field="field"/>
7702 <description>
7703 The class to query.
7704 </description>
7705 </param>
7706 <param id="field">
7707 <jfieldID class="klass"/>
7708 <description>
7709 The field to query.
7710 </description>
7711 </param>
7712 <param id="modifiers_ptr">
7713 <outptr><jint/></outptr>
7714 <description>
7715 On return, points to the access flags.
7716 </description>
7717 </param>
7718 </parameters>
7719 <errors>
7720 </errors>
7721 </function>
7723 <function id="IsFieldSynthetic" phase="start" num="63">
7724 <synopsis>Is Field Synthetic</synopsis>
7725 <description>
7726 For the field indicated by <code>klass</code> and <code>field</code>, return a
7727 value indicating whether the field is synthetic via <code>is_synthetic_ptr</code>.
7728 Synthetic fields are generated by the compiler but not present in the
7729 original source code.
7730 </description>
7731 <origin>jvmdi</origin>
7732 <capabilities>
7733 <required id="can_get_synthetic_attribute"></required>
7734 </capabilities>
7735 <parameters>
7736 <param id="klass">
7737 <jclass field="field"/>
7738 <description>
7739 The class of the field to query.
7740 </description>
7741 </param>
7742 <param id="field">
7743 <jfieldID class="klass"/>
7744 <description>
7745 The field to query.
7746 </description>
7747 </param>
7748 <param id="is_synthetic_ptr">
7749 <outptr><jboolean/></outptr>
7750 <description>
7751 On return, points to the boolean result of this function.
7752 </description>
7753 </param>
7754 </parameters>
7755 <errors>
7756 </errors>
7757 </function>
7759 </category>
7761 <category id="method" label="Method">
7763 <intro>
7764 These functions provide information about a method (represented as a
7765 <typelink id="jmethodID"/>) and set how methods are processed.
7766 </intro>
7768 <intro id="obsoleteMethods" label="Obsolete Methods">
7769 The functions <functionlink id="RetransformClasses"/> and
7770 <functionlink id="RedefineClasses"/> can cause new versions
7771 of methods to be installed.
7772 An original version of a method is considered equivalent
7773 to the new version if:
7774 <ul>
7775 <li>their bytecodes are the same except for indices into the
7776 constant pool and </li>
7777 <li>the referenced constants are equal.</li>
7778 </ul>
7779 An original method version which is not equivalent to the
7780 new method version is called obsolete and is assigned a new method ID;
7781 the original method ID now refers to the new method version.
7782 A method ID can be tested for obsolescence with
7783 <functionlink id="IsMethodObsolete"/>.
7784 </intro>
7786 <function id="GetMethodName" phase="start" num="64">
7787 <synopsis>Get Method Name (and Signature)</synopsis>
7788 <description>
7789 For the method indicated by <code>method</code>,
7790 return the method name via <code>name_ptr</code> and method signature via
7791 <code>signature_ptr</code>.
7792 <p/>
7793 Method signatures are defined in the JNI Specification and are
7794 referred to as <code>method descriptors</code> in
7795 <vmspec chapter="4.3.3"/>.
7796 Note this is different
7797 than method signatures as defined in the <i>Java Language Specification</i>.
7798 </description>
7799 <origin>jvmdiClone</origin>
7800 <capabilities>
7801 </capabilities>
7802 <parameters>
7803 <param id="method">
7804 <jmethodID/>
7805 <description>
7806 The method to query.
7807 </description>
7808 </param>
7809 <param id="name_ptr">
7810 <allocbuf>
7811 <char/>
7812 <nullok>the name is not returned</nullok>
7813 </allocbuf>
7814 <description>
7815 On return, points to the method name, encoded as a
7816 <internallink id="mUTF">modified UTF-8</internallink> string.
7817 </description>
7818 </param>
7819 <param id="signature_ptr">
7820 <allocbuf>
7821 <char/>
7822 <nullok>the signature is not returned</nullok>
7823 </allocbuf>
7824 <description>
7825 On return, points to the method signature, encoded as a
7826 <internallink id="mUTF">modified UTF-8</internallink> string.
7827 </description>
7828 </param>
7829 <param id="generic_ptr">
7830 <allocbuf>
7831 <char/>
7832 <nullok>the generic signature is not returned</nullok>
7833 </allocbuf>
7834 <description>
7835 On return, points to the generic signature of the method, encoded as a
7836 <internallink id="mUTF">modified UTF-8</internallink> string.
7837 If there is no generic signature attribute for the method, then,
7838 on return, points to <code>NULL</code>.
7839 </description>
7840 </param>
7841 </parameters>
7842 <errors>
7843 </errors>
7844 </function>
7846 <function id="GetMethodDeclaringClass" phase="start" num="65">
7847 <synopsis>Get Method Declaring Class</synopsis>
7848 <description>
7849 For the method indicated by <code>method</code>,
7850 return the class that defined it via <code>declaring_class_ptr</code>.
7851 </description>
7852 <origin>jvmdi</origin>
7853 <capabilities>
7854 </capabilities>
7855 <parameters>
7856 <param id="klass">
7857 <jclass method="method"/>
7858 <description>
7859 The class to query.
7860 </description>
7861 </param>
7862 <param id="method">
7863 <jmethodID class="klass"/>
7864 <description>
7865 The method to query.
7866 </description>
7867 </param>
7868 <param id="declaring_class_ptr">
7869 <outptr><jclass/></outptr>
7870 <description>
7871 On return, points to the declaring class
7872 </description>
7873 </param>
7874 </parameters>
7875 <errors>
7876 </errors>
7877 </function>
7879 <function id="GetMethodModifiers" phase="start" num="66">
7880 <synopsis>Get Method Modifiers</synopsis>
7881 <description>
7882 For the method indicated by <code>method</code>,
7883 return the access flags via <code>modifiers_ptr</code>.
7884 Access flags are defined in <vmspec chapter="4"/>.
7885 </description>
7886 <origin>jvmdi</origin>
7887 <capabilities>
7888 </capabilities>
7889 <parameters>
7890 <param id="klass">
7891 <jclass method="method"/>
7892 <description>
7893 The class to query.
7894 </description>
7895 </param>
7896 <param id="method">
7897 <jmethodID class="klass"/>
7898 <description>
7899 The method to query.
7900 </description>
7901 </param>
7902 <param id="modifiers_ptr">
7903 <outptr><jint/></outptr>
7904 <description>
7905 On return, points to the access flags.
7906 </description>
7907 </param>
7908 </parameters>
7909 <errors>
7910 </errors>
7911 </function>
7913 <function id="GetMaxLocals" phase="start" num="68">
7914 <synopsis>Get Max Locals</synopsis>
7915 <description>
7916 For the method indicated by <code>method</code>,
7917 return the number of local variable slots used by the method,
7918 including the local variables used to pass parameters to the
7919 method on its invocation.
7920 <p/>
7921 See <code>max_locals</code> in <vmspec chapter="4.7.3"/>.
7922 </description>
7923 <origin>jvmdi</origin>
7924 <capabilities>
7925 </capabilities>
7926 <parameters>
7927 <param id="klass">
7928 <jclass method="method"/>
7929 <description>
7930 The class to query.
7931 </description>
7932 </param>
7933 <param id="method">
7934 <jmethodID class="klass" native="error"/>
7935 <description>
7936 The method to query.
7937 </description>
7938 </param>
7939 <param id="max_ptr">
7940 <outptr><jint/></outptr>
7941 <description>
7942 On return, points to the maximum number of local slots
7943 </description>
7944 </param>
7945 </parameters>
7946 <errors>
7947 </errors>
7948 </function>
7950 <function id="GetArgumentsSize" phase="start" num="69">
7951 <synopsis>Get Arguments Size</synopsis>
7952 <description>
7953 For the method indicated by <code>method</code>,
7954 return via <code>max_ptr</code> the number of local variable slots used
7955 by the method's arguments.
7956 Note that two-word arguments use two slots.
7957 </description>
7958 <origin>jvmdi</origin>
7959 <capabilities>
7960 </capabilities>
7961 <parameters>
7962 <param id="klass">
7963 <jclass method="method"/>
7964 <description>
7965 The class to query.
7966 </description>
7967 </param>
7968 <param id="method">
7969 <jmethodID class="klass" native="error"/>
7970 <description>
7971 The method to query.
7972 </description>
7973 </param>
7974 <param id="size_ptr">
7975 <outptr><jint/></outptr>
7976 <description>
7977 On return, points to the number of argument slots
7978 </description>
7979 </param>
7980 </parameters>
7981 <errors>
7982 </errors>
7983 </function>
7985 <function id="GetLineNumberTable" phase="start" num="70">
7986 <synopsis>Get Line Number Table</synopsis>
7987 <typedef id="jvmtiLineNumberEntry" label="Line number table entry">
7988 <field id="start_location">
7989 <jlocation/>
7990 <description>
7991 the <datalink id="jlocation"></datalink> where the line begins
7992 </description>
7993 </field>
7994 <field id="line_number">
7995 <jint/>
7996 <description>
7997 the line number
7998 </description>
7999 </field>
8000 </typedef>
8001 <description>
8002 For the method indicated by <code>method</code>,
8003 return a table of source line number entries. The size of the table is
8004 returned via <code>entry_count_ptr</code> and the table itself is
8005 returned via <code>table_ptr</code>.
8006 </description>
8007 <origin>jvmdi</origin>
8008 <capabilities>
8009 <required id="can_get_line_numbers"></required>
8010 </capabilities>
8011 <parameters>
8012 <param id="klass">
8013 <jclass method="method"/>
8014 <description>
8015 The class to query.
8016 </description>
8017 </param>
8018 <param id="method">
8019 <jmethodID class="klass" native="error"/>
8020 <description>
8021 The method to query.
8022 </description>
8023 </param>
8024 <param id="entry_count_ptr">
8025 <outptr><jint/></outptr>
8026 <description>
8027 On return, points to the number of entries in the table
8028 </description>
8029 </param>
8030 <param id="table_ptr">
8031 <allocbuf outcount="entry_count_ptr"><struct>jvmtiLineNumberEntry</struct></allocbuf>
8032 <description>
8033 On return, points to the line number table pointer.
8034 </description>
8035 </param>
8036 </parameters>
8037 <errors>
8038 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8039 Class information does not include line numbers.
8040 </error>
8041 </errors>
8042 </function>
8044 <function id="GetMethodLocation" phase="start" num="71">
8045 <synopsis>Get Method Location</synopsis>
8046 <description>
8047 For the method indicated by <code>method</code>,
8048 return the beginning and ending addresses through
8049 <code>start_location_ptr</code> and <code>end_location_ptr</code>. In a
8050 conventional byte code indexing scheme,
8051 <code>start_location_ptr</code> will always point to zero
8052 and <code>end_location_ptr</code>
8053 will always point to the byte code count minus one.
8054 </description>
8055 <origin>jvmdi</origin>
8056 <capabilities>
8057 </capabilities>
8058 <parameters>
8059 <param id="klass">
8060 <jclass method="method"/>
8061 <description>
8062 The class to query.
8063 </description>
8064 </param>
8065 <param id="method">
8066 <jmethodID class="klass" native="error"/>
8067 <description>
8068 The method to query.
8069 </description>
8070 </param>
8071 <param id="start_location_ptr">
8072 <outptr><jlocation/></outptr>
8073 <description>
8074 On return, points to the first location, or
8075 <code>-1</code> if location information is not available.
8076 If the information is available and
8077 <functionlink id="GetJLocationFormat"></functionlink>
8078 returns <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>
8079 then this will always be zero.
8080 </description>
8081 </param>
8082 <param id="end_location_ptr">
8083 <outptr><jlocation/></outptr>
8084 <description>
8085 On return, points to the last location,
8086 or <code>-1</code> if location information is not available.
8087 </description>
8088 </param>
8089 </parameters>
8090 <errors>
8091 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8092 Class information does not include method sizes.
8093 </error>
8094 </errors>
8095 </function>
8097 <function id="GetLocalVariableTable" num="72">
8098 <synopsis>Get Local Variable Table</synopsis>
8099 <typedef id="jvmtiLocalVariableEntry" label="Local variable table entry">
8100 <field id="start_location">
8101 <jlocation/>
8102 <description>
8103 The code array index where the local variable is first valid
8104 (that is, where it must have a value).
8105 </description>
8106 </field>
8107 <field id="length">
8108 <jint/>
8109 <description>
8110 The length of the valid section for this local variable.
8111 The last code array index where the local variable is valid
8112 is <code>start_location + length</code>.
8113 </description>
8114 </field>
8115 <field id="name">
8116 <allocfieldbuf><char/></allocfieldbuf>
8117 <description>
8118 The local variable name, encoded as a
8119 <internallink id="mUTF">modified UTF-8</internallink> string.
8120 </description>
8121 </field>
8122 <field id="signature">
8123 <allocfieldbuf><char/></allocfieldbuf>
8124 <description>
8125 The local variable's type signature, encoded as a
8126 <internallink id="mUTF">modified UTF-8</internallink> string.
8127 The signature format is the same as that defined in
8128 <vmspec chapter="4.3.2"/>.
8129 </description>
8130 </field>
8131 <field id="generic_signature">
8132 <allocfieldbuf><char/></allocfieldbuf>
8133 <description>
8134 The local variable's generic signature, encoded as a
8135 <internallink id="mUTF">modified UTF-8</internallink> string.
8136 The value of this field will be <code>NULL</code> for any local
8137 variable which does not have a generic type.
8138 </description>
8139 </field>
8140 <field id="slot">
8141 <jint/>
8142 <description>
8143 The local variable's slot. See <internallink id="local">Local Variables</internallink>.
8144 </description>
8145 </field>
8146 </typedef>
8147 <description>
8148 Return local variable information.
8149 </description>
8150 <origin>jvmdiClone</origin>
8151 <capabilities>
8152 <required id="can_access_local_variables"></required>
8153 </capabilities>
8154 <parameters>
8155 <param id="method">
8156 <jmethodID native="error"/>
8157 <description>
8158 The method to query.
8159 </description>
8160 </param>
8161 <param id="entry_count_ptr">
8162 <outptr><jint/></outptr>
8163 <description>
8164 On return, points to the number of entries in the table
8165 </description>
8166 </param>
8167 <param id="table_ptr">
8168 <allocbuf outcount="entry_count_ptr"><struct>jvmtiLocalVariableEntry</struct></allocbuf>
8169 <description>
8170 On return, points to an array of local variable table entries.
8171 </description>
8172 </param>
8173 </parameters>
8174 <errors>
8175 <error id="JVMTI_ERROR_ABSENT_INFORMATION">
8176 Class information does not include local variable
8177 information.
8178 </error>
8179 </errors>
8180 </function>
8182 <function id="GetBytecodes" phase="start" num="75">
8183 <synopsis>Get Bytecodes</synopsis>
8184 <description>
8185 For the method indicated by <code>method</code>,
8186 return the byte codes that implement the method. The number of
8187 bytecodes is returned via <code>bytecode_count_ptr</code>. The byte codes
8188 themselves are returned via <code>bytecodes_ptr</code>.
8189 </description>
8190 <origin>jvmdi</origin>
8191 <capabilities>
8192 <required id="can_get_bytecodes"></required>
8193 </capabilities>
8194 <parameters>
8195 <param id="klass">
8196 <jclass method="method"/>
8197 <description>
8198 The class to query.
8199 </description>
8200 </param>
8201 <param id="method">
8202 <jmethodID class="klass" native="error"/>
8203 <description>
8204 The method to query.
8205 </description>
8206 </param>
8207 <param id="bytecode_count_ptr">
8208 <outptr><jint/></outptr>
8209 <description>
8210 On return, points to the length of the byte code array
8211 </description>
8212 </param>
8213 <param id="bytecodes_ptr">
8214 <allocbuf outcount="bytecode_count_ptr"><uchar/></allocbuf>
8215 <description>
8216 On return, points to the pointer to the byte code array
8217 </description>
8218 </param>
8219 </parameters>
8220 <errors>
8221 </errors>
8222 </function>
8224 <function id="IsMethodNative" phase="start" num="76">
8225 <synopsis>Is Method Native</synopsis>
8226 <description>
8227 For the method indicated by <code>method</code>, return a
8228 value indicating whether the method is native via <code>is_native_ptr</code>
8229 </description>
8230 <origin>jvmdi</origin>
8231 <capabilities>
8232 </capabilities>
8233 <parameters>
8234 <param id="klass">
8235 <jclass method="method"/>
8236 <description>
8237 The class to query.
8238 </description>
8239 </param>
8240 <param id="method">
8241 <jmethodID class="klass"/>
8242 <description>
8243 The method to query.
8244 </description>
8245 </param>
8246 <param id="is_native_ptr">
8247 <outptr><jboolean/></outptr>
8248 <description>
8249 On return, points to the boolean result of this function.
8250 </description>
8251 </param>
8252 </parameters>
8253 <errors>
8254 </errors>
8255 </function>
8257 <function id="IsMethodSynthetic" phase="start" num="77">
8258 <synopsis>Is Method Synthetic</synopsis>
8259 <description>
8260 For the method indicated by <code>method</code>, return a
8261 value indicating whether the method is synthetic via <code>is_synthetic_ptr</code>.
8262 Synthetic methods are generated by the compiler but not present in the
8263 original source code.
8264 </description>
8265 <origin>jvmdi</origin>
8266 <capabilities>
8267 <required id="can_get_synthetic_attribute"></required>
8268 </capabilities>
8269 <parameters>
8270 <param id="klass">
8271 <jclass method="method"/>
8272 <description>
8273 The class to query.
8274 </description>
8275 </param>
8276 <param id="method">
8277 <jmethodID class="klass"/>
8278 <description>
8279 The method to query.
8280 </description>
8281 </param>
8282 <param id="is_synthetic_ptr">
8283 <outptr><jboolean/></outptr>
8284 <description>
8285 On return, points to the boolean result of this function.
8286 </description>
8287 </param>
8288 </parameters>
8289 <errors>
8290 </errors>
8291 </function>
8293 <function id="IsMethodObsolete" phase="start" num="91">
8294 <synopsis>Is Method Obsolete</synopsis>
8295 <description>
8296 Determine if a method ID refers to an
8297 <internallink id="obsoleteMethods">obsolete</internallink>
8298 method version.
8299 </description>
8300 <origin>jvmdi</origin>
8301 <capabilities>
8302 </capabilities>
8303 <parameters>
8304 <param id="klass">
8305 <jclass method="method"/>
8306 <description>
8307 The class to query.
8308 </description>
8309 </param>
8310 <param id="method">
8311 <jmethodID class="klass"/>
8312 <description>
8313 The method ID to query.
8314 </description>
8315 </param>
8316 <param id="is_obsolete_ptr">
8317 <outptr><jboolean/></outptr>
8318 <description>
8319 On return, points to the boolean result of this function.
8320 </description>
8321 </param>
8322 </parameters>
8323 <errors>
8324 </errors>
8325 </function>
8327 <function id="SetNativeMethodPrefix" jkernel="yes" phase="any" num="73" since="1.1">
8328 <synopsis>Set Native Method Prefix</synopsis>
8329 <description>
8330 This function modifies the failure handling of
8331 native method resolution by allowing retry
8332 with a prefix applied to the name.
8333 When used with the
8334 <eventlink id="ClassFileLoadHook">ClassFileLoadHook
8335 event</eventlink>, it enables native methods to be
8336 <internallink id="bci">instrumented</internallink>.
8337 <p/>
8338 Since native methods cannot be directly instrumented
8339 (they have no bytecodes), they must be wrapped with
8340 a non-native method which can be instrumented.
8341 For example, if we had:
8342 <example>
8343 native boolean foo(int x);</example>
8344 <p/>
8345 We could transform the class file (with the
8346 ClassFileLoadHook event) so that this becomes:
8347 <example>
8348 boolean foo(int x) {
8349 <i>... record entry to foo ...</i>
8350 return wrapped_foo(x);
8351 }
8353 native boolean wrapped_foo(int x);</example>
8354 <p/>
8355 Where foo becomes a wrapper for the actual native method
8356 with the appended prefix "wrapped_". Note that
8357 "wrapped_" would be a poor choice of prefix since it
8358 might conceivably form the name of an existing method
8359 thus something like "$$$MyAgentWrapped$$$_" would be
8360 better but would make these examples less readable.
8361 <p/>
8362 The wrapper will allow data to be collected on the native
8363 method call, but now the problem becomes linking up the
8364 wrapped method with the native implementation.
8365 That is, the method <code>wrapped_foo</code> needs to be
8366 resolved to the native implementation of <code>foo</code>,
8367 which might be:
8368 <example>
8369 Java_somePackage_someClass_foo(JNIEnv* env, jint x)</example>
8370 <p/>
8371 This function allows the prefix to be specified and the
8372 proper resolution to occur.
8373 Specifically, when the standard resolution fails, the
8374 resolution is retried taking the prefix into consideration.
8375 There are two ways that resolution occurs, explicit
8376 resolution with the JNI function <code>RegisterNatives</code>
8377 and the normal automatic resolution. For
8378 <code>RegisterNatives</code>, the VM will attempt this
8379 association:
8380 <example>
8381 method(foo) -> nativeImplementation(foo)</example>
8382 <p/>
8383 When this fails, the resolution will be retried with
8384 the specified prefix prepended to the method name,
8385 yielding the correct resolution:
8386 <example>
8387 method(wrapped_foo) -> nativeImplementation(foo)</example>
8388 <p/>
8389 For automatic resolution, the VM will attempt:
8390 <example>
8391 method(wrapped_foo) -> nativeImplementation(wrapped_foo)</example>
8392 <p/>
8393 When this fails, the resolution will be retried with
8394 the specified prefix deleted from the implementation name,
8395 yielding the correct resolution:
8396 <example>
8397 method(wrapped_foo) -> nativeImplementation(foo)</example>
8398 <p/>
8399 Note that since the prefix is only used when standard
8400 resolution fails, native methods can be wrapped selectively.
8401 <p/>
8402 Since each <jvmti/> environment is independent and
8403 can do its own transformation of the bytecodes, more
8404 than one layer of wrappers may be applied. Thus each
8405 environment needs its own prefix. Since transformations
8406 are applied in order, the prefixes, if applied, will
8407 be applied in the same order.
8408 The order of transformation application is described in
8409 the <eventlink id="ClassFileLoadHook"/> event.
8410 Thus if three environments applied
8411 wrappers, <code>foo</code> might become
8412 <code>$env3_$env2_$env1_foo</code>. But if, say,
8413 the second environment did not apply a wrapper to
8414 <code>foo</code> it would be just
8415 <code>$env3_$env1_foo</code>. To be able to
8416 efficiently determine the sequence of prefixes,
8417 an intermediate prefix is only applied if its non-native
8418 wrapper exists. Thus, in the last example, even though
8419 <code>$env1_foo</code> is not a native method, the
8420 <code>$env1_</code> prefix is applied since
8421 <code>$env1_foo</code> exists.
8422 <p/>
8423 Since the prefixes are used at resolution time
8424 and since resolution may be arbitrarily delayed, a
8425 native method prefix must remain set as long as there
8426 are corresponding prefixed native methods.
8427 </description>
8428 <origin>new</origin>
8429 <capabilities>
8430 <required id="can_set_native_method_prefix"></required>
8431 </capabilities>
8432 <parameters>
8433 <param id="prefix">
8434 <inbuf>
8435 <char/>
8436 <nullok>
8437 any existing prefix in this environment is cancelled
8438 </nullok>
8439 </inbuf>
8440 <description>
8441 The prefix to apply, encoded as a
8442 <internallink id="mUTF">modified UTF-8</internallink> string.
8443 </description>
8444 </param>
8445 </parameters>
8446 <errors>
8447 </errors>
8448 </function>
8450 <function id="SetNativeMethodPrefixes" jkernel="yes" phase="any" num="74" since="1.1">
8451 <synopsis>Set Native Method Prefixes</synopsis>
8452 <description>
8453 For a normal agent, <functionlink id="SetNativeMethodPrefix"/>
8454 will provide all needed native method prefixing.
8455 For a meta-agent that performs multiple independent class
8456 file transformations (for example as a proxy for another
8457 layer of agents) this function allows each transformation
8458 to have its own prefix.
8459 The prefixes are applied in the order supplied and are
8460 processed in the same manor as described for the
8461 application of prefixes from multiple <jvmti/> environments
8462 in <functionlink id="SetNativeMethodPrefix"/>.
8463 <p/>
8464 Any previous prefixes are replaced. Thus, calling this
8465 function with a <paramlink id="prefix_count"/> of <code>0</code>
8466 disables prefixing in this environment.
8467 <p/>
8468 <functionlink id="SetNativeMethodPrefix"/> and this function
8469 are the two ways to set the prefixes.
8470 Calling <code>SetNativeMethodPrefix</code> with
8471 a prefix is the same as calling this function with
8472 <paramlink id="prefix_count"/> of <code>1</code>.
8473 Calling <code>SetNativeMethodPrefix</code> with
8474 <code>NULL</code> is the same as calling this function with
8475 <paramlink id="prefix_count"/> of <code>0</code>.
8476 </description>
8477 <origin>new</origin>
8478 <capabilities>
8479 <required id="can_set_native_method_prefix"></required>
8480 </capabilities>
8481 <parameters>
8482 <param id="prefix_count">
8483 <jint min="0"/>
8484 <description>
8485 The number of prefixes to apply.
8486 </description>
8487 </param>
8488 <param id="prefixes">
8489 <agentbuf>
8490 <char/>
8491 </agentbuf>
8492 <description>
8493 The prefixes to apply for this environment, each encoded as a
8494 <internallink id="mUTF">modified UTF-8</internallink> string.
8495 </description>
8496 </param>
8497 </parameters>
8498 <errors>
8499 </errors>
8500 </function>
8502 </category>
8504 <category id="RawMonitors" label="Raw Monitor">
8506 <function id="CreateRawMonitor" phase="onload" callbacksafe="safe" num="31">
8507 <synopsis>Create Raw Monitor</synopsis>
8508 <description>
8509 Create a raw monitor.
8510 </description>
8511 <origin>jvmdi</origin>
8512 <capabilities>
8513 </capabilities>
8514 <parameters>
8515 <param id="name">
8516 <inbuf><char/></inbuf>
8517 <description>
8518 A name to identify the monitor, encoded as a
8519 <internallink id="mUTF">modified UTF-8</internallink> string.
8520 </description>
8521 </param>
8522 <param id="monitor_ptr">
8523 <outptr><jrawMonitorID/></outptr>
8524 <description>
8525 On return, points to the created monitor.
8526 </description>
8527 </param>
8528 </parameters>
8529 <errors>
8530 </errors>
8531 </function>
8533 <function id="DestroyRawMonitor" phase="onload" callbacksafe="safe" num="32">
8534 <synopsis>Destroy Raw Monitor</synopsis>
8535 <description>
8536 Destroy the raw monitor.
8537 If the monitor being destroyed has been entered by this thread, it will be
8538 exited before it is destroyed.
8539 If the monitor being destroyed has been entered by another thread,
8540 an error will be returned and the monitor will not be destroyed.
8541 </description>
8542 <origin>jvmdi</origin>
8543 <capabilities>
8544 </capabilities>
8545 <parameters>
8546 <param id="monitor">
8547 <jrawMonitorID/>
8548 <description>
8549 The monitor
8550 </description>
8551 </param>
8552 </parameters>
8553 <errors>
8554 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8555 Not monitor owner
8556 </error>
8557 </errors>
8558 </function>
8560 <function id="RawMonitorEnter" phase="any" callbacksafe="safe" impl="innative notrace" num="33">
8561 <synopsis>Raw Monitor Enter</synopsis>
8562 <description>
8563 Gain exclusive ownership of a raw monitor.
8564 The same thread may enter a monitor more then once.
8565 The thread must
8566 <functionlink id="RawMonitorExit">exit</functionlink>
8567 the monitor the same number of times as it is entered.
8568 If a monitor is entered during <code>OnLoad</code> (before attached threads exist)
8569 and has not exited when attached threads come into existence, the enter
8570 is considered to have occurred on the main thread.
8571 </description>
8572 <origin>jvmdi</origin>
8573 <capabilities>
8574 </capabilities>
8575 <parameters>
8576 <param id="monitor">
8577 <jrawMonitorID/>
8578 <description>
8579 The monitor
8580 </description>
8581 </param>
8582 </parameters>
8583 <errors>
8584 </errors>
8585 </function>
8587 <function id="RawMonitorExit" phase="any" callbacksafe="safe" impl="innative notrace" num="34">
8588 <synopsis>Raw Monitor Exit</synopsis>
8589 <description>
8590 Release exclusive ownership of a raw monitor.
8591 </description>
8592 <origin>jvmdi</origin>
8593 <capabilities>
8594 </capabilities>
8595 <parameters>
8596 <param id="monitor">
8597 <jrawMonitorID/>
8598 <description>
8599 The monitor
8600 </description>
8601 </param>
8602 </parameters>
8603 <errors>
8604 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8605 Not monitor owner
8606 </error>
8607 </errors>
8608 </function>
8610 <function id="RawMonitorWait" phase="any" callbacksafe="safe" impl="innative notrace" num="35">
8611 <synopsis>Raw Monitor Wait</synopsis>
8612 <description>
8613 Wait for notification of the raw monitor.
8614 <p/>
8615 Causes the current thread to wait until either another thread calls
8616 <functionlink id="RawMonitorNotify"/> or
8617 <functionlink id="RawMonitorNotifyAll"/>
8618 for the specified raw monitor, or the specified
8619 <paramlink id="millis">timeout</paramlink>
8620 has elapsed.
8621 </description>
8622 <origin>jvmdi</origin>
8623 <capabilities>
8624 </capabilities>
8625 <parameters>
8626 <param id="monitor">
8627 <jrawMonitorID/>
8628 <description>
8629 The monitor
8630 </description>
8631 </param>
8632 <param id="millis">
8633 <jlong/>
8634 <description>
8635 The timeout, in milliseconds. If the timeout is
8636 zero, then real time is not taken into consideration
8637 and the thread simply waits until notified.
8638 </description>
8639 </param>
8640 </parameters>
8641 <errors>
8642 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8643 Not monitor owner
8644 </error>
8645 <error id="JVMTI_ERROR_INTERRUPT">
8646 Wait was interrupted, try again
8647 </error>
8648 </errors>
8649 </function>
8651 <function id="RawMonitorNotify" phase="any" callbacksafe="safe" impl="notrace" num="36">
8652 <synopsis>Raw Monitor Notify</synopsis>
8653 <description>
8654 Notify a single thread waiting on the raw monitor.
8655 </description>
8656 <origin>jvmdi</origin>
8657 <capabilities>
8658 </capabilities>
8659 <parameters>
8660 <param id="monitor">
8661 <jrawMonitorID/>
8662 <description>
8663 The monitor
8664 </description>
8665 </param>
8666 </parameters>
8667 <errors>
8668 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8669 Not monitor owner
8670 </error>
8671 </errors>
8672 </function>
8674 <function id="RawMonitorNotifyAll" phase="any" callbacksafe="safe" impl="notrace" num="37">
8675 <synopsis>Raw Monitor Notify All</synopsis>
8676 <description>
8677 Notify all threads waiting on the raw monitor.
8678 </description>
8679 <origin>jvmdi</origin>
8680 <capabilities>
8681 </capabilities>
8682 <parameters>
8683 <param id="monitor">
8684 <jrawMonitorID/>
8685 <description>
8686 The monitor
8687 </description>
8688 </param>
8689 </parameters>
8690 <errors>
8691 <error id="JVMTI_ERROR_NOT_MONITOR_OWNER">
8692 Not monitor owner
8693 </error>
8694 </errors>
8695 </function>
8697 <elide>
8698 <function id="GetRawMonitorUse" num="118">
8699 <synopsis>Get Raw Monitor Use</synopsis>
8700 <description>
8701 The fields of the <functionlink id="jvmtiMonitorUsage"></functionlink> structure
8702 are filled in with information about usage of the raw monitor.
8703 </description>
8704 <origin>new</origin>
8705 <capabilities>
8706 <required id="can_get_raw_monitor_usage"></required>
8707 </capabilities>
8708 <parameters>
8709 <param id="monitor">
8710 <jrawMonitorID/>
8711 <description>
8712 the raw monitor to query.
8713 </description>
8714 </param>
8715 <param id="info_ptr">
8716 <outptr><struct>jvmtiMonitorUsage</struct></outptr>
8717 <description>
8718 On return, filled with monitor information for the
8719 specified raw monitor.
8720 </description>
8721 </param>
8722 </parameters>
8723 <errors>
8724 </errors>
8725 </function>
8727 <function id="GetRawMonitors" num="119">
8728 <synopsis>Get Raw Monitors</synopsis>
8729 <description>
8730 Return the list of raw monitors.
8731 <p/>
8732 Note: details about each monitor can be examined with
8733 <functionlink id="GetRawMonitorUse"></functionlink>.
8734 </description>
8735 <origin>new</origin>
8736 <capabilities>
8737 <required id="can_get_raw_monitor_usage"></required>
8738 </capabilities>
8739 <parameters>
8740 <param id="monitorCnt">
8741 <outptr><jint/></outptr>
8742 <description>
8743 On return, pointer to the number
8744 of monitors returned in <code>monitors_ptr</code>.
8745 </description>
8746 </param>
8747 <param id="monitors_ptr">
8748 <allocbuf outcount="monitorCnt"><jrawMonitorID/></allocbuf>
8749 <description>
8750 On return, pointer to the monitor list.
8751 </description>
8752 </param>
8753 </parameters>
8754 <errors>
8755 </errors>
8756 </function>
8757 </elide>
8758 </category>
8760 <category id="jniIntercept" label="JNI Function Interception">
8762 <intro>
8763 Provides the ability to intercept and resend
8764 Java Native Interface (JNI) function calls
8765 by manipulating the JNI function table.
8766 See <externallink id="http://java.sun.com/javase/6/docs/guide/jni/spec/functions.html">JNI
8767 Functions</externallink> in the <i>Java Native Interface Specification</i>.
8768 <p/>
8769 The following example illustrates intercepting the
8770 <code>NewGlobalRef</code> JNI call in order to count reference
8771 creation.
8772 <example>
8773 JNIEnv original_jni_Functions;
8774 JNIEnv redirected_jni_Functions;
8775 int my_global_ref_count = 0;
8777 jobject
8778 MyNewGlobalRef(JNIEnv *jni_env, jobject lobj) {
8779 ++my_global_ref_count;
8780 return originalJNIFunctions->NewGlobalRef(env, lobj);
8781 }
8783 void
8784 myInit() {
8785 jvmtiError err;
8787 err = (*jvmti_env)->GetJNIFunctionTable(jvmti_env, &original_jni_Functions);
8788 if (err != JVMTI_ERROR_NONE) {
8789 die();
8790 }
8791 err = (*jvmti_env)->GetJNIFunctionTable(jvmti_env, &redirected_jni_Functions);
8792 if (err != JVMTI_ERROR_NONE) {
8793 die();
8794 }
8795 redirectedJNIFunctions->NewGlobalRef = MyNewGlobalRef;
8796 err = (*jvmti_env)->SetJNIFunctionTable(jvmti_env, redirected_jni_Functions);
8797 if (err != JVMTI_ERROR_NONE) {
8798 die();
8799 }
8800 }
8801 </example>
8802 Sometime after <code>myInit</code> is called the user's JNI
8803 code is executed which makes the call to create a new global
8804 reference. Instead of going to the normal JNI implementation
8805 the call goes to <code>myNewGlobalRef</code>. Note that a
8806 copy of the original function table is kept so that the normal
8807 JNI function can be called after the data is collected.
8808 Note also that any JNI functions which are not overwritten
8809 will behave normally.
8810 <todo>
8811 check that the example compiles and executes.
8812 </todo>
8813 </intro>
8815 <function id="SetJNIFunctionTable" phase="start" num="120">
8816 <synopsis>Set JNI Function Table</synopsis>
8817 <description>
8818 Set the JNI function table
8819 in all current and future JNI environments.
8820 As a result, all future JNI calls are directed to the specified functions.
8821 Use <functionlink id="GetJNIFunctionTable"></functionlink> to get the
8822 function table to pass to this function.
8823 For this function to take effect the the updated table entries must be
8824 used by the JNI clients.
8825 Since the table is defined <code>const</code> some compilers may optimize
8826 away the access to the table, thus preventing this function from taking
8827 effect.
8828 The table is copied--changes to the local copy of the
8829 table have no effect.
8830 This function affects only the function table, all other aspects of the environment are
8831 unaffected.
8832 See the examples <internallink id="jniIntercept">above</internallink>.
8833 </description>
8834 <origin>new</origin>
8835 <capabilities>
8836 </capabilities>
8837 <parameters>
8838 <param id="function_table">
8839 <inptr>
8840 <struct>jniNativeInterface</struct>
8841 </inptr>
8842 <description>
8843 Points to the new JNI function table.
8844 </description>
8845 </param>
8846 </parameters>
8847 <errors>
8848 </errors>
8849 </function>
8851 <function id="GetJNIFunctionTable" phase="start" num="121">
8852 <synopsis>Get JNI Function Table</synopsis>
8853 <description>
8854 Get the JNI function table.
8855 The JNI function table is copied into allocated memory.
8856 If <functionlink id="SetJNIFunctionTable"></functionlink>
8857 has been called, the modified (not the original) function
8858 table is returned.
8859 Only the function table is copied, no other aspects of the environment
8860 are copied.
8861 See the examples <internallink id="jniIntercept">above</internallink>.
8862 </description>
8863 <origin>new</origin>
8864 <capabilities>
8865 </capabilities>
8866 <parameters>
8867 <param id="function_table">
8868 <allocbuf>
8869 <struct>jniNativeInterface</struct>
8870 </allocbuf>
8871 <description>
8872 On return, <code>*function_table</code>
8873 points a newly allocated copy of the JNI function table.
8874 </description>
8875 </param>
8876 </parameters>
8877 <errors>
8878 </errors>
8879 </function>
8881 </category>
8883 <category id="eventManagement" label="Event Management">
8885 <function id="SetEventCallbacks" jkernel="yes" phase="onload" num="122">
8886 <synopsis>Set Event Callbacks</synopsis>
8887 <description>
8888 Set the functions to be called for each event.
8889 The callbacks are specified by supplying a replacement function table.
8890 The function table is copied--changes to the local copy of the
8891 table have no effect.
8892 This is an atomic action, all callbacks are set at once.
8893 No events are sent before this function is called.
8894 When an entry is <code>NULL</code> or when the event is beyond
8895 <paramlink id="size_of_callbacks"></paramlink> no event is sent.
8896 Details on events are
8897 described <internallink id="EventSection">later</internallink> in this document.
8898 An event must be enabled and have a callback in order to be
8899 sent--the order in which this function and
8900 <functionlink id="SetEventNotificationMode"></functionlink>
8901 are called does not affect the result.
8902 </description>
8903 <origin>new</origin>
8904 <capabilities>
8905 </capabilities>
8906 <parameters>
8907 <param id="callbacks">
8908 <inptr>
8909 <struct>jvmtiEventCallbacks</struct>
8910 <nullok>remove the existing callbacks</nullok>
8911 </inptr>
8912 <description>
8913 The new event callbacks.
8914 </description>
8915 </param>
8916 <param id="size_of_callbacks">
8917 <jint min="0"/>
8918 <description>
8919 <code>sizeof(jvmtiEventCallbacks)</code>--for version
8920 compatibility.
8921 </description>
8922 </param>
8923 </parameters>
8924 <errors>
8925 </errors>
8926 </function>
8928 <function id="SetEventNotificationMode" jkernel="yes" phase="onload" num="2">
8929 <synopsis>Set Event Notification Mode</synopsis>
8930 <description>
8931 Control the generation of events.
8932 <constants id="jvmtiEventMode" label="Event Enable/Disable" kind="enum">
8933 <constant id="JVMTI_ENABLE" num="1">
8934 If <paramlink id="mode"></paramlink> is <code>JVMTI_ENABLE</code>,
8935 the event <paramlink id="event_type"></paramlink> will be enabled
8936 </constant>
8937 <constant id="JVMTI_DISABLE" num="0">
8938 If <paramlink id="mode"></paramlink> is <code>JVMTI_DISABLE</code>,
8939 the event <paramlink id="event_type"></paramlink> will be disabled
8940 </constant>
8941 </constants>
8942 If <code>thread</code> is <code>NULL</code>,
8943 the event is enabled or disabled globally; otherwise, it is
8944 enabled or disabled for a particular thread.
8945 An event is generated for
8946 a particular thread if it is enabled either at the thread or global
8947 levels.
8948 <p/>
8949 See <internallink id="EventIndex">below</internallink> for information on specific events.
8950 <p/>
8951 The following events cannot be controlled at the thread
8952 level through this function.
8953 <ul>
8954 <li><eventlink id="VMInit"></eventlink></li>
8955 <li><eventlink id="VMStart"></eventlink></li>
8956 <li><eventlink id="VMDeath"></eventlink></li>
8957 <li><eventlink id="ThreadStart"></eventlink></li>
8958 <li><eventlink id="CompiledMethodLoad"></eventlink></li>
8959 <li><eventlink id="CompiledMethodUnload"></eventlink></li>
8960 <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
8961 <li><eventlink id="DataDumpRequest"></eventlink></li>
8962 </ul>
8963 <p/>
8964 Initially, no events are enabled at either the thread level
8965 or the global level.
8966 <p/>
8967 Any needed capabilities (see Event Enabling Capabilities below) must be possessed
8968 before calling this function.
8969 <p/>
8970 Details on events are
8971 described <internallink id="EventSection">below</internallink>.
8972 </description>
8973 <origin>jvmdiClone</origin>
8974 <eventcapabilities></eventcapabilities>
8975 <parameters>
8976 <param id="mode">
8977 <enum>jvmtiEventMode</enum>
8978 <description>
8979 <code>JVMTI_ENABLE</code> or <code>JVMTI_DISABLE</code>
8980 </description>
8981 </param>
8982 <param id="event_type">
8983 <enum>jvmtiEvent</enum>
8984 <description>
8985 the event to control
8986 </description>
8987 </param>
8988 <param id="event_thread">
8989 <ptrtype>
8990 <jthread impl="noconvert"/>
8991 <nullok>event is controlled at the global level</nullok>
8992 </ptrtype>
8993 <description>
8994 The thread to control
8995 </description>
8996 </param>
8997 <param id="...">
8998 <varargs/>
8999 <description>
9000 for future expansion
9001 </description>
9002 </param>
9003 </parameters>
9004 <errors>
9005 <error id="JVMTI_ERROR_INVALID_THREAD">
9006 <paramlink id="event_thread"/> is non-<code>NULL</code> and is not a valid thread.
9007 </error>
9008 <error id="JVMTI_ERROR_THREAD_NOT_ALIVE">
9009 <paramlink id="event_thread"/> is non-<code>NULL</code> and is not live (has not been started or is now dead).
9010 </error>
9011 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9012 thread level control was attempted on events which do not
9013 permit thread level control.
9014 </error>
9015 <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9016 The Required Event Enabling Capability is not possessed.
9017 </error>
9018 </errors>
9019 </function>
9021 <function id="GenerateEvents" num="123">
9022 <synopsis>Generate Events</synopsis>
9023 <description>
9024 Generate events to represent the current state of the VM.
9025 For example, if <paramlink id="event_type"/> is
9026 <code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code>,
9027 a <eventlink id="CompiledMethodLoad"></eventlink> event will be
9028 sent for each currently compiled method.
9029 Methods that were loaded and now have been unloaded are not sent.
9030 The history of what events have previously been sent does not
9031 effect what events are sent by this function--for example,
9032 all currently compiled methods
9033 will be sent each time this function is called.
9034 <p/>
9035 This function is useful when
9036 events may have been missed due to the agent attaching after program
9037 execution begins; this function generates the missed events.
9038 <p/>
9039 Attempts to execute Java programming language code or
9040 JNI functions may be paused until this function returns -
9041 so neither should be called from the thread sending the event.
9042 This function returns only after the missed events have been
9043 sent, processed and have returned.
9044 The event may be sent on a different thread than the thread
9045 on which the event occurred.
9046 The callback for the event must be set with
9047 <functionlink id="SetEventCallbacks"></functionlink>
9048 and the event must be enabled with
9049 <functionlink id="SetEventNotificationMode"></functionlink>
9050 or the events will not occur.
9051 If the VM no longer has the information to generate some or
9052 all of the requested events, the events are simply not sent -
9053 no error is returned.
9054 <p/>
9055 Only the following events are supported:
9056 <ul>
9057 <li><eventlink id="CompiledMethodLoad"></eventlink></li>
9058 <li><eventlink id="DynamicCodeGenerated"></eventlink></li>
9059 </ul>
9060 </description>
9061 <origin>new</origin>
9062 <capabilities>
9063 <capability id="can_generate_compiled_method_load_events"></capability>
9064 </capabilities>
9065 <parameters>
9066 <param id="event_type">
9067 <enum>jvmtiEvent</enum>
9068 <description>
9069 The type of event to generate. Must be one of these:
9070 <ul>
9071 <li><eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink></li>
9072 <li><eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink></li>
9073 </ul>
9074 </description>
9075 </param>
9076 </parameters>
9077 <errors>
9078 <error id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY">
9079 <paramlink id="event_type"/> is
9080 <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9081 and <fieldlink id="can_generate_compiled_method_load_events" struct="jvmtiCapabilities"></fieldlink>
9082 is <code>false</code>.
9083 </error>
9084 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9085 <paramlink id="event_type"/> is other than
9086 <eventlink id="CompiledMethodLoad"><code>JVMTI_EVENT_COMPILED_METHOD_LOAD</code></eventlink>
9087 or <eventlink id="DynamicCodeGenerated"><code>JVMTI_EVENT_DYNAMIC_CODE_GENERATED</code></eventlink>.
9088 </error>
9089 </errors>
9090 </function>
9092 </category>
9094 <category id="extension" label="Extension Mechanism">
9096 <intro>
9097 These functions
9098 allow a <jvmti/> implementation to provide functions and events
9099 beyond those defined in this specification.
9100 <p/>
9101 Both extension functions and extension events have parameters
9102 each of which has a 'type' and 'kind' chosen from the following tables:
9104 <constants id="jvmtiParamTypes" label="Extension Function/Event Parameter Types" kind="enum">
9105 <constant id="JVMTI_TYPE_JBYTE" num="101">
9106 Java programming language primitive type - <code>byte</code>.
9107 JNI type <code>jbyte</code>.
9108 </constant>
9109 <constant id="JVMTI_TYPE_JCHAR" num="102">
9110 Java programming language primitive type - <code>char</code>.
9111 JNI type <code>jchar</code>.
9112 </constant>
9113 <constant id="JVMTI_TYPE_JSHORT" num="103">
9114 Java programming language primitive type - <code>short</code>.
9115 JNI type <code>jshort</code>.
9116 </constant>
9117 <constant id="JVMTI_TYPE_JINT" num="104">
9118 Java programming language primitive type - <code>int</code>.
9119 JNI type <datalink id="jint"></datalink>.
9120 </constant>
9121 <constant id="JVMTI_TYPE_JLONG" num="105">
9122 Java programming language primitive type - <code>long</code>.
9123 JNI type <datalink id="jlong"></datalink>.
9124 </constant>
9125 <constant id="JVMTI_TYPE_JFLOAT" num="106">
9126 Java programming language primitive type - <code>float</code>.
9127 JNI type <datalink id="jfloat"></datalink>.
9128 </constant>
9129 <constant id="JVMTI_TYPE_JDOUBLE" num="107">
9130 Java programming language primitive type - <code>double</code>.
9131 JNI type <datalink id="jdouble"></datalink>.
9132 </constant>
9133 <constant id="JVMTI_TYPE_JBOOLEAN" num="108">
9134 Java programming language primitive type - <code>boolean</code>.
9135 JNI type <datalink id="jboolean"></datalink>.
9136 </constant>
9137 <constant id="JVMTI_TYPE_JOBJECT" num="109">
9138 Java programming language object type - <code>java.lang.Object</code>.
9139 JNI type <datalink id="jobject"></datalink>.
9140 Returned values are JNI local references and must be managed.
9141 </constant>
9142 <constant id="JVMTI_TYPE_JTHREAD" num="110">
9143 Java programming language object type - <code>java.lang.Thread</code>.
9144 <jvmti/> type <datalink id="jthread"></datalink>.
9145 Returned values are JNI local references and must be managed.
9146 </constant>
9147 <constant id="JVMTI_TYPE_JCLASS" num="111">
9148 Java programming language object type - <code>java.lang.Class</code>.
9149 JNI type <datalink id="jclass"></datalink>.
9150 Returned values are JNI local references and must be managed.
9151 </constant>
9152 <constant id="JVMTI_TYPE_JVALUE" num="112">
9153 Union of all Java programming language primitive and object types -
9154 JNI type <datalink id="jvalue"></datalink>.
9155 Returned values which represent object types are JNI local references and must be managed.
9156 </constant>
9157 <constant id="JVMTI_TYPE_JFIELDID" num="113">
9158 Java programming language field identifier -
9159 JNI type <datalink id="jfieldID"></datalink>.
9160 </constant>
9161 <constant id="JVMTI_TYPE_JMETHODID" num="114">
9162 Java programming language method identifier -
9163 JNI type <datalink id="jmethodID"></datalink>.
9164 </constant>
9165 <constant id="JVMTI_TYPE_CCHAR" num="115">
9166 C programming language type - <code>char</code>.
9167 </constant>
9168 <constant id="JVMTI_TYPE_CVOID" num="116">
9169 C programming language type - <code>void</code>.
9170 </constant>
9171 <constant id="JVMTI_TYPE_JNIENV" num="117">
9172 JNI environment - <code>JNIEnv</code>.
9173 Should be used with the correct <datalink id="jvmtiParamKind"/> to make it a pointer type.
9174 </constant>
9175 </constants>
9177 <constants id="jvmtiParamKind" label="Extension Function/Event Parameter Kinds" kind="enum">
9178 <constant id="JVMTI_KIND_IN" num="91">
9179 Ingoing argument - <code>foo</code>.
9180 </constant>
9181 <constant id="JVMTI_KIND_IN_PTR" num="92">
9182 Ingoing pointer argument - <code>const foo*</code>.
9183 </constant>
9184 <constant id="JVMTI_KIND_IN_BUF" num="93">
9185 Ingoing array argument - <code>const foo*</code>.
9186 </constant>
9187 <constant id="JVMTI_KIND_ALLOC_BUF" num="94">
9188 Outgoing allocated array argument - <code>foo**</code>.
9189 Free with <code>Deallocate</code>.
9190 </constant>
9191 <constant id="JVMTI_KIND_ALLOC_ALLOC_BUF" num="95">
9192 Outgoing allocated array of allocated arrays argument - <code>foo***</code>.
9193 Free with <code>Deallocate</code>.
9194 </constant>
9195 <constant id="JVMTI_KIND_OUT" num="96">
9196 Outgoing argument - <code>foo*</code>.
9197 </constant>
9198 <constant id="JVMTI_KIND_OUT_BUF" num="97">
9199 Outgoing array argument (pre-allocated by agent) - <code>foo*</code>.
9200 Do not <code>Deallocate</code>.
9201 </constant>
9202 </constants>
9204 </intro>
9206 <typedef id="jvmtiParamInfo" label="Extension Function/Event Parameter Info">
9207 <field id="name">
9208 <allocfieldbuf><char/></allocfieldbuf>
9209 <description>
9210 The parameter name, encoded as a
9211 <internallink id="mUTF">modified UTF-8</internallink> string
9212 </description>
9213 </field>
9214 <field id="kind">
9215 <enum>jvmtiParamKind</enum>
9216 <description>
9217 The kind of the parameter - type modifiers
9218 </description>
9219 </field>
9220 <field id="base_type">
9221 <enum>jvmtiParamTypes</enum>
9222 <description>
9223 The base type of the parameter - modified by <code>kind</code>
9224 </description>
9225 </field>
9226 <field id="null_ok">
9227 <jboolean/>
9228 <description>
9229 Is a <code>NULL</code> argument permitted? Applies only to pointer and object types.
9230 </description>
9231 </field>
9232 </typedef>
9234 <callback id="jvmtiExtensionFunction">
9235 <enum>jvmtiError</enum>
9236 <synopsis>Extension Function</synopsis>
9237 <description>
9238 This is the implementation-specific extension function.
9239 </description>
9240 <parameters>
9241 <param id="jvmti_env">
9242 <outptr>
9243 <struct>jvmtiEnv</struct>
9244 </outptr>
9245 <description>
9246 The <jvmti/> environment is the only fixed parameter for extension functions.
9247 </description>
9248 </param>
9249 <param id="...">
9250 <varargs/>
9251 <description>
9252 The extension function-specific parameters
9253 </description>
9254 </param>
9255 </parameters>
9256 </callback>
9258 <function id="GetExtensionFunctions" phase="onload" num="124">
9259 <synopsis>Get Extension Functions</synopsis>
9261 <typedef id="jvmtiExtensionFunctionInfo" label="Extension Function Info">
9262 <field id="func">
9263 <ptrtype>
9264 <struct>jvmtiExtensionFunction</struct>
9265 </ptrtype>
9266 <description>
9267 The actual function to call
9268 </description>
9269 </field>
9270 <field id="id">
9271 <allocfieldbuf><char/></allocfieldbuf>
9272 <description>
9273 The identifier for the extension function, encoded as a
9274 <internallink id="mUTF">modified UTF-8</internallink> string.
9275 Uses package name conventions.
9276 For example, <code>com.sun.hotspot.bar</code>
9277 </description>
9278 </field>
9279 <field id="short_description">
9280 <allocfieldbuf><char/></allocfieldbuf>
9281 <description>
9282 A one sentence description of the function, encoded as a
9283 <internallink id="mUTF">modified UTF-8</internallink> string.
9284 </description>
9285 </field>
9286 <field id="param_count">
9287 <jint/>
9288 <description>
9289 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9290 </description>
9291 </field>
9292 <field id="params">
9293 <allocfieldbuf outcount="param_count">
9294 <struct>jvmtiParamInfo</struct>
9295 </allocfieldbuf>
9296 <description>
9297 Array of
9298 <fieldlink id="param_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9299 parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9300 </description>
9301 </field>
9302 <field id="error_count">
9303 <jint/>
9304 <description>
9305 The number of possible error returns (excluding universal errors)
9306 </description>
9307 </field>
9308 <field id="errors">
9309 <allocfieldbuf outcount="error_count">
9310 <enum>jvmtiError</enum>
9311 </allocfieldbuf>
9312 <description>
9313 Array of <fieldlink id="error_count" struct="jvmtiExtensionFunctionInfo"></fieldlink>
9314 possible errors
9315 </description>
9316 </field>
9317 </typedef>
9319 <description>
9320 Returns the set of extension functions.
9321 </description>
9322 <origin>new</origin>
9323 <capabilities>
9324 </capabilities>
9325 <parameters>
9326 <param id="extension_count_ptr">
9327 <outptr><jint/></outptr>
9328 <description>
9329 On return, points to the number of extension functions
9330 </description>
9331 </param>
9332 <param id="extensions">
9333 <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionFunctionInfo</struct></allocbuf>
9334 <description>
9335 Returns an array of extension function info, one per function
9336 </description>
9337 </param>
9338 </parameters>
9339 <errors>
9340 </errors>
9341 </function>
9343 <function id="GetExtensionEvents" phase="onload" num="125">
9344 <synopsis>Get Extension Events</synopsis>
9346 <typedef id="jvmtiExtensionEventInfo" label="Extension Event Info">
9347 <field id="extension_event_index">
9348 <jint/>
9349 <description>
9350 The identifying index of the event
9351 </description>
9352 </field>
9353 <field id="id">
9354 <allocfieldbuf><char/></allocfieldbuf>
9355 <description>
9356 The identifier for the extension event, encoded as a
9357 <internallink id="mUTF">modified UTF-8</internallink> string.
9358 Uses package name conventions.
9359 For example, <code>com.sun.hotspot.bar</code>
9360 </description>
9361 </field>
9362 <field id="short_description">
9363 <allocfieldbuf><char/></allocfieldbuf>
9364 <description>
9365 A one sentence description of the event, encoded as a
9366 <internallink id="mUTF">modified UTF-8</internallink> string.
9367 </description>
9368 </field>
9369 <field id="param_count">
9370 <jint/>
9371 <description>
9372 The number of parameters excluding <code>jvmtiEnv *jvmti_env</code>
9373 </description>
9374 </field>
9375 <field id="params">
9376 <allocfieldbuf outcount="param_count">
9377 <struct>jvmtiParamInfo</struct>
9378 </allocfieldbuf>
9379 <description>
9380 Array of
9381 <fieldlink id="param_count" struct="jvmtiExtensionEventInfo"></fieldlink>
9382 parameters (<code>jvmtiEnv *jvmti_env</code> excluded)
9383 </description>
9384 </field>
9385 </typedef>
9387 <description>
9388 Returns the set of extension events.
9389 </description>
9390 <origin>new</origin>
9391 <capabilities>
9392 </capabilities>
9393 <parameters>
9394 <param id="extension_count_ptr">
9395 <outptr><jint/></outptr>
9396 <description>
9397 On return, points to the number of extension events
9398 </description>
9399 </param>
9400 <param id="extensions">
9401 <allocbuf outcount="extension_count_ptr"><struct>jvmtiExtensionEventInfo</struct></allocbuf>
9402 <description>
9403 Returns an array of extension event info, one per event
9404 </description>
9405 </param>
9406 </parameters>
9407 <errors>
9408 </errors>
9409 </function>
9411 <callback id="jvmtiExtensionEvent">
9412 <void/>
9413 <synopsis>Extension Event</synopsis>
9414 <description>
9415 This is the implementation-specific event.
9416 The event handler is set with
9417 <functionlink id="SetExtensionEventCallback"/>.
9418 <p/>
9419 Event handlers for extension events must be declared varargs to match this definition.
9420 Failure to do so could result in calling convention mismatch and undefined behavior
9421 on some platforms.
9422 <p/>
9423 For example, if the <code>jvmtiParamInfo</code>
9424 returned by <functionlink id="GetExtensionEvents"/> indicates that
9425 there is a <code>jint</code> parameter, the event handler should be
9426 declared:
9427 <example>
9428 void JNICALL myHandler(jvmtiEnv* jvmti_env, jint myInt, ...)
9429 </example>
9430 Note the terminal "<code>...</code>" which indicates varargs.
9431 </description>
9432 <parameters>
9433 <param id="jvmti_env">
9434 <outptr>
9435 <struct>jvmtiEnv</struct>
9436 </outptr>
9437 <description>
9438 The <jvmti/> environment is the only fixed parameter for extension events.
9439 </description>
9440 </param>
9441 <param id="...">
9442 <varargs/>
9443 <description>
9444 The extension event-specific parameters
9445 </description>
9446 </param>
9447 </parameters>
9448 </callback>
9450 <function id="SetExtensionEventCallback" phase="onload" num="126">
9451 <synopsis>Set Extension Event Callback</synopsis>
9453 <description>
9454 Sets the callback function for an extension event and
9455 enables the event. Or, if the callback is <code>NULL</code>, disables
9456 the event. Note that unlike standard events, setting
9457 the callback and enabling the event are a single operation.
9458 </description>
9459 <origin>new</origin>
9460 <capabilities>
9461 </capabilities>
9462 <parameters>
9463 <param id="extension_event_index">
9464 <jint/>
9465 <description>
9466 Identifies which callback to set.
9467 This index is the
9468 <fieldlink id="extension_event_index" struct="jvmtiExtensionEventInfo"></fieldlink>
9469 field of
9470 <datalink id="jvmtiExtensionEventInfo"/>.
9471 </description>
9472 </param>
9473 <param id="callback">
9474 <ptrtype>
9475 <struct>jvmtiExtensionEvent</struct>
9476 <nullok>disable the event</nullok>
9477 </ptrtype>
9478 <description>
9479 If <code>callback</code> is non-<code>NULL</code>,
9480 set <code>callback</code> to be the event callback function
9481 and enable the event.
9482 </description>
9483 </param>
9484 </parameters>
9485 <errors>
9486 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
9487 <paramlink id="extension_event_index"/> is not an
9488 <fieldlink id="extension_event_index"
9489 struct="jvmtiExtensionEventInfo"/>
9490 returned by
9491 <functionlink id="GetExtensionEvents"/>
9492 </error>
9493 </errors>
9494 </function>
9496 </category>
9498 <category id="capability" label="Capability">
9500 <intro>
9501 The capabilities functions allow you to change the
9502 functionality available to <jvmti/>--that is,
9503 which <jvmti/>
9504 functions can be called, what events can be generated,
9505 and what functionality these events and functions can
9506 provide.
9507 <p/>
9508 The "Capabilities" section of each function and event describe which
9509 capabilities, if any, they are associated with. "Required Functionality"
9510 means it is available for use and no capabilities must be added to use it.
9511 "Optional Functionality" means the agent must possess the capability
9512 before it can be used.
9513 To possess a capability, the agent must
9514 <functionlink id="AddCapabilities">add the capability</functionlink>.
9515 "Optional Features" describe capabilities which,
9516 if added, extend the feature set.
9517 <p/>
9518 The potentially available capabilities of each <jvmti/> implementation are different.
9519 Depending on the implementation, a capability:
9520 <ul>
9521 <li>may never be added</li>
9522 <li>may be added in either the <code>OnLoad</code> or live phase in any environment</li>
9523 <li>may be added only during the <code>OnLoad</code> phase</li>
9524 <li>may be possessed by only one environment at a time</li>
9525 <li>may be possessed by only one environment at a time,
9526 and only during the <code>OnLoad</code> phase</li>
9527 <li>and so on ...</li>
9528 </ul>
9529 Frequently, the addition of a capability may incur a cost in execution speed, start up
9530 time, and/or memory footprint. Note that the overhead of using a capability
9531 is completely different than the overhead of possessing a capability.
9532 Take single stepping as an example. When single stepping is on (that
9533 is, when the event is enabled and thus actively sending events)
9534 the overhead of sending and processing an event
9535 on each instruction is huge in any implementation.
9536 However, the overhead of possessing the capability may be small or large,
9537 depending on the implementation. Also, when and if a capability is potentially
9538 available depends on the implementation. Some examples:
9539 <ul>
9540 <li>One VM might perform all execution by compiling bytecodes into
9541 native code and be unable to generate single step instructions.
9542 In this implementation the capability can not be added.</li>
9543 <li>Another VM may be able to switch execution to a single stepping
9544 interpreter at any time. In this implementation, having the capability has no
9545 overhead and could be added at any time.</li>
9546 <li>Yet another VM might be able to choose a bytecode compiling or single stepping capable interpreted
9547 execution engine at start up, but be unable to switch between them.
9548 In this implementation the capability would need to be added
9549 during the <code>OnLoad</code> phase (before bytecode
9550 execution begins) and would have a large impact on execution speed
9551 even if single stepping was never used.</li>
9552 <li>Still another VM might be able to add an "is single stepping on" check
9553 into compiled bytecodes or a generated interpreter. Again in this implementation
9554 the capability would need to be added during the <code>OnLoad</code> phase but the overhead (a test
9555 and branch on each instruction) would be considerably less.</li>
9556 </ul>
9557 <p/>
9558 Each <jvmti/> <internallink id="environments">environment</internallink>
9559 has its own set of capabilities.
9560 Initially, that set is empty.
9561 Any desired capability must be added.
9562 If possible, capabilities should be added during the <code>OnLoad</code> phase. For most
9563 virtual machines certain capabilities require special set up for
9564 the virtual machine and this set up must happen
9565 during the <code>OnLoad</code> phase, before the virtual machine begins execution.
9566 Once a capability is added, it can
9567 only be removed if explicitly relinquished by the environment.
9568 <p/>
9569 The agent can,
9570 <functionlink id="GetPotentialCapabilities">determine what
9571 capabilities this VM can potentially provide</functionlink>,
9572 <functionlink id="AddCapabilities">add the capabilities
9573 to be used</functionlink>,
9574 <functionlink id="RelinquishCapabilities">release capabilities
9575 which are no longer needed</functionlink>, and
9576 <functionlink id="GetCapabilities">examine the currently available
9577 capabilities</functionlink>.
9578 </intro>
9580 <intro id="capabilityExamples" label="Capability Examples">
9581 For example, a freshly started agent (in the <code>OnLoad</code> function)
9582 wants to enable all possible capabilities.
9583 Note that, in general, this is not advisable as the agent may suffer
9584 a performance penalty for functionality it is not using.
9585 The code might look like this in C:
9586 <example>
9587 jvmtiCapabilities capa;
9588 jvmtiError err;
9590 err = (*jvmti)->GetPotentialCapabilities(jvmti, &capa);
9591 if (err == JVMTI_ERROR_NONE) {
9592 err = (*jvmti)->AddCapabilities(jvmti, &capa);
9593 </example>
9594 For example, if an agent wants to check if it can get
9595 the bytecodes of a method (that is, it wants to check
9596 if it previously added this capability and has not
9597 relinquished it), the code might
9598 look like this in C:
9599 <example>
9600 jvmtiCapabilities capa;
9601 jvmtiError err;
9603 err = (*jvmti)->GetCapabilities(jvmti, &capa);
9604 if (err == JVMTI_ERROR_NONE) {
9605 if (capa.can_get_bytecodes) { ... } }
9606 </example>
9607 </intro>
9609 <capabilitiestypedef id="jvmtiCapabilities" label="The Capabilities Structure">
9610 <description>
9611 The functions in this category use this capabilities structure
9612 which contains boolean flags corresponding to each capability:
9613 </description>
9614 <capabilityfield id="can_tag_objects">
9615 <description>
9616 Can set and get tags, as described in the
9617 <internallink id="Heap">Heap category</internallink>.
9618 </description>
9619 </capabilityfield>
9620 <capabilityfield id="can_generate_field_modification_events">
9621 <description>
9622 Can set watchpoints on field modification -
9623 <functionlink id="SetFieldModificationWatch"></functionlink>
9624 </description>
9625 </capabilityfield>
9626 <capabilityfield id="can_generate_field_access_events">
9627 <description>
9628 Can set watchpoints on field access -
9629 <functionlink id="SetFieldAccessWatch"></functionlink>
9630 </description>
9631 </capabilityfield>
9632 <capabilityfield id="can_get_bytecodes">
9633 <description>
9634 Can get bytecodes of a method <functionlink id="GetBytecodes"></functionlink>
9635 </description>
9636 </capabilityfield>
9637 <capabilityfield id="can_get_synthetic_attribute">
9638 <description>
9639 Can test if a field or method is synthetic -
9640 <functionlink id="IsFieldSynthetic"></functionlink> and
9641 <functionlink id="IsMethodSynthetic"></functionlink>
9642 </description>
9643 </capabilityfield>
9644 <capabilityfield id="can_get_owned_monitor_info">
9645 <description>
9646 Can get information about ownership of monitors -
9647 <functionlink id="GetOwnedMonitorInfo"></functionlink>
9648 </description>
9649 </capabilityfield>
9650 <capabilityfield id="can_get_current_contended_monitor">
9651 <description>
9652 Can <functionlink id="GetCurrentContendedMonitor"></functionlink>
9653 </description>
9654 </capabilityfield>
9655 <capabilityfield id="can_get_monitor_info">
9656 <description>
9657 Can <functionlink id="GetObjectMonitorUsage"></functionlink>
9658 </description>
9659 </capabilityfield>
9660 <capabilityfield id="can_pop_frame">
9661 <description>
9662 Can pop frames off the stack - <functionlink id="PopFrame"></functionlink>
9663 </description>
9664 </capabilityfield>
9665 <capabilityfield id="can_redefine_classes">
9666 <description>
9667 Can redefine classes with <functionlink id="RedefineClasses"/>.
9668 </description>
9669 </capabilityfield>
9670 <capabilityfield id="can_signal_thread">
9671 <description>
9672 Can send stop or interrupt to threads
9673 </description>
9674 </capabilityfield>
9675 <capabilityfield id="can_get_source_file_name">
9676 <description>
9677 Can get the source file name of a class
9678 </description>
9679 </capabilityfield>
9680 <capabilityfield id="can_get_line_numbers">
9681 <description>
9682 Can get the line number table of a method
9683 </description>
9684 </capabilityfield>
9685 <capabilityfield id="can_get_source_debug_extension">
9686 <description>
9687 Can get the source debug extension of a class
9688 </description>
9689 </capabilityfield>
9690 <capabilityfield id="can_access_local_variables">
9691 <description>
9692 Can set and get local variables
9693 </description>
9694 </capabilityfield>
9695 <capabilityfield id="can_maintain_original_method_order">
9696 <description>
9697 Can return methods in the order they occur in the class file
9698 </description>
9699 </capabilityfield>
9700 <capabilityfield id="can_generate_single_step_events">
9701 <description>
9702 Can get <eventlink id="SingleStep">single step</eventlink> events
9703 </description>
9704 </capabilityfield>
9705 <capabilityfield id="can_generate_exception_events">
9706 <description>
9707 Can get <eventlink id="Exception">exception thrown</eventlink> and
9708 <eventlink id="ExceptionCatch">exception catch</eventlink> events
9709 </description>
9710 </capabilityfield>
9711 <capabilityfield id="can_generate_frame_pop_events">
9712 <description>
9713 Can <functionlink id="NotifyFramePop">set</functionlink> and thus get
9714 <eventlink id="FramePop"></eventlink> events
9715 </description>
9716 </capabilityfield>
9717 <capabilityfield id="can_generate_breakpoint_events">
9718 <description>
9719 Can <functionlink id="SetBreakpoint">set</functionlink> and thus get
9720 <eventlink id="Breakpoint"></eventlink> events
9721 </description>
9722 </capabilityfield>
9723 <capabilityfield id="can_suspend">
9724 <description>
9725 Can suspend and resume threads
9726 </description>
9727 </capabilityfield>
9728 <capabilityfield id="can_redefine_any_class">
9729 <description>
9730 Can modify (retransform or redefine) any non-primitive non-array class.
9731 See <functionlink id="IsModifiableClass"/>.
9732 </description>
9733 </capabilityfield>
9734 <capabilityfield id="can_get_current_thread_cpu_time">
9735 <description>
9736 Can <functionlink id="GetCurrentThreadCpuTime">get</functionlink>
9737 current thread CPU time
9738 </description>
9739 </capabilityfield>
9740 <capabilityfield id="can_get_thread_cpu_time">
9741 <description>
9742 Can <functionlink id="GetThreadCpuTime">get</functionlink>
9743 thread CPU time
9744 </description>
9745 </capabilityfield>
9746 <capabilityfield id="can_generate_method_entry_events"
9747 disp1="can_generate" disp2="_method_entry_events"
9748 >
9749 <description>
9750 Can generate method entry events on entering a method
9751 </description>
9752 </capabilityfield>
9753 <capabilityfield id="can_generate_method_exit_events"
9754 disp1="can_generate" disp2="_method_exit_events"
9755 >
9756 <description>
9757 Can generate method exit events on leaving a method
9758 </description>
9759 </capabilityfield>
9760 <capabilityfield id="can_generate_all_class_hook_events"
9761 disp1="can_generate" disp2="_all_class_hook_events"
9762 >
9763 <description>
9764 Can generate ClassFileLoadHook events for every loaded class.
9765 </description>
9766 </capabilityfield>
9767 <capabilityfield id="can_generate_compiled_method_load_events"
9768 disp1="can_generate" disp2="_compiled_method_load_events"
9769 >
9770 <description>
9771 Can generate events when a method is compiled or unloaded
9772 </description>
9773 </capabilityfield>
9774 <capabilityfield id="can_generate_monitor_events"
9775 disp1="can_generate" disp2="_monitor_events"
9776 >
9777 <description>
9778 Can generate events on monitor activity
9779 </description>
9780 </capabilityfield>
9781 <capabilityfield id="can_generate_vm_object_alloc_events"
9782 disp1="can_generate" disp2="_vm_object_alloc_events"
9783 >
9784 <description>
9785 Can generate events on VM allocation of an object
9786 </description>
9787 </capabilityfield>
9788 <capabilityfield id="can_generate_native_method_bind_events"
9789 disp1="can_generate" disp2="_native_method_bind_events"
9790 >
9791 <description>
9792 Can generate events when a native method is bound to its
9793 implementation
9794 </description>
9795 </capabilityfield>
9796 <capabilityfield id="can_generate_garbage_collection_events"
9797 disp1="can_generate" disp2="_garbage_collection_events"
9798 >
9799 <description>
9800 Can generate events when garbage collection begins or ends
9801 </description>
9802 </capabilityfield>
9803 <capabilityfield id="can_generate_object_free_events"
9804 disp1="can_generate" disp2="_object_free_events"
9805 >
9806 <description>
9807 Can generate events when the garbage collector frees an object
9808 </description>
9809 </capabilityfield>
9810 <capabilityfield id="can_force_early_return" since="1.1">
9811 <description>
9812 Can return early from a method, as described in the
9813 <internallink id="ForceEarlyReturn">Force Early Return category</internallink>.
9814 </description>
9815 </capabilityfield>
9816 <capabilityfield id="can_get_owned_monitor_stack_depth_info" since="1.1">
9817 <description>
9818 Can get information about owned monitors with stack depth -
9819 <functionlink id="GetOwnedMonitorStackDepthInfo"></functionlink>
9820 </description>
9821 </capabilityfield>
9822 <capabilityfield id="can_get_constant_pool" since="1.1">
9823 <description>
9824 Can get the constant pool of a class -
9825 <functionlink id="GetConstantPool"></functionlink>
9826 </description>
9827 </capabilityfield>
9828 <capabilityfield id="can_set_native_method_prefix" since="1.1">
9829 <description>
9830 Can set prefix to be applied when native method cannot be resolved -
9831 <functionlink id="SetNativeMethodPrefix"/> and
9832 <functionlink id="SetNativeMethodPrefixes"/>
9833 </description>
9834 </capabilityfield>
9835 <capabilityfield id="can_retransform_classes" since="1.1">
9836 <description>
9837 Can retransform classes with <functionlink id="RetransformClasses"/>.
9838 In addition to the restrictions imposed by the specific
9839 implementation on this capability (see the
9840 <internallink id="capability">Capability</internallink> section),
9841 this capability must be set before the
9842 <eventlink id="ClassFileLoadHook"/> event is enabled for the
9843 first time in this environment.
9844 An environment that possesses this capability at the time that
9845 <code>ClassFileLoadHook</code> is enabled for the first time is
9846 said to be <i>retransformation capable</i>.
9847 An environment that does not possess this capability at the time that
9848 <code>ClassFileLoadHook</code> is enabled for the first time is
9849 said to be <i>retransformation incapable</i>.
9850 </description>
9851 </capabilityfield>
9852 <capabilityfield id="can_retransform_any_class" since="1.1">
9853 <description>
9854 <functionlink id="RetransformClasses"/> can be called on any class
9855 (<fieldlink id="can_retransform_classes" struct="jvmtiCapabilities"/>
9856 must also be set)
9857 </description>
9858 </capabilityfield>
9859 <capabilityfield id="can_generate_resource_exhaustion_heap_events" since="1.1">
9860 <description>
9861 Can generate events when the VM is unable to allocate memory from
9862 the <tm>Java</tm> platform heap.
9863 See <eventlink id="ResourceExhausted"/>.
9864 </description>
9865 </capabilityfield>
9866 <capabilityfield id="can_generate_resource_exhaustion_threads_events" since="1.1">
9867 <description>
9868 Can generate events when the VM is unable to create a thread.
9869 See <eventlink id="ResourceExhausted"/>.
9870 </description>
9871 </capabilityfield>
9872 </capabilitiestypedef>
9874 <function id="GetPotentialCapabilities" jkernel="yes" phase="onload" num="140">
9875 <synopsis>Get Potential Capabilities</synopsis>
9876 <description>
9877 Returns via <paramlink id="capabilities_ptr"></paramlink> the <jvmti/>
9878 features that can potentially be possessed by this environment
9879 at this time.
9880 The returned capabilities differ from the complete set of capabilities
9881 implemented by the VM in two cases: another environment possesses
9882 capabilities that can only be possessed by one environment, or the
9883 current <functionlink id="GetPhase">phase</functionlink> is live,
9884 and certain capabilities can only be added during the <code>OnLoad</code> phase.
9885 The <functionlink id="AddCapabilities"></functionlink> function
9886 may be used to set any or all or these capabilities.
9887 Currently possessed capabilities are included.
9888 <p/>
9889 Typically this function is used in the <code>OnLoad</code> function.
9890 Some virtual machines may allow a limited set of capabilities to be
9891 added in the live phase.
9892 In this case, the set of potentially available capabilities
9893 will likely differ from the <code>OnLoad</code> phase set.
9894 <p/>
9895 See the
9896 <internallink id="capabilityExamples">Capability Examples</internallink>.
9897 </description>
9898 <origin>new</origin>
9899 <capabilities>
9900 </capabilities>
9901 <parameters>
9902 <param id="capabilities_ptr">
9903 <outptr><struct>jvmtiCapabilities</struct></outptr>
9904 <description>
9905 On return, points to the <jvmti/> capabilities that may be added.
9906 </description>
9907 </param>
9908 </parameters>
9909 <errors>
9910 </errors>
9911 </function>
9913 <elide>
9914 <function id="EstimateCostOfCapabilities" phase="onload" num="141">
9915 <synopsis>Estimate Cost Of Capabilities</synopsis>
9916 <description>
9917 <issue>There is strong opposition to this function. The concern is
9918 that it would be difficult or impossible to provide meaningful
9919 numbers, as the amount of impact is conditional on many factors
9920 that a single number could not represent. There is doubt that
9921 conditional implementations would be used or are even a good idea.
9922 The thought is that release documentation for the implementation
9923 would be the best means of exposing this information.
9924 Unless new arguments are presented, I intend to remove this
9925 function in the next revision.
9926 </issue>
9927 <p/>
9928 Return via the <paramlink id="time_impact_ptr"></paramlink> and
9929 <paramlink id="space_impact_ptr"></paramlink> an estimate of the impact
9930 of adding the capabilities pointed to by
9931 <paramlink id="capabilities_ptr"></paramlink>.
9932 The returned estimates are in percentage of additional overhead, thus
9933 a time impact of 100 mean the application might run
9934 at half the speed.
9935 The estimates are very rough approximations and are not guaranteed.
9936 Note also, that the estimates are of the impact of having the
9937 capability available--when and if it is used the impact may be
9938 much greater.
9939 Estimates can be for a single capability or for a set of
9940 capabilities. Note that the costs are not necessarily additive,
9941 adding support for one capability might make another available
9942 for free or conversely having two capabilities at once may
9943 have multiplicative impact.
9944 Estimates are relative to the current set of capabilities -
9945 that is, how much more impact given the currently possessed capabilities.
9946 <p/>
9947 Typically this function is used in the OnLoad function,
9948 some virtual machines may allow a limited set of capabilities to be
9949 added in the live phase.
9950 In this case, the set of potentially available capabilities
9951 will likely differ from the OnLoad phase set.
9952 <p/>
9953 See the
9954 <internallink id="capabilityExamples">Capability Examples</internallink>.
9955 </description>
9956 <origin>new</origin>
9957 <capabilities>
9958 </capabilities>
9959 <parameters>
9960 <param id="capabilities_ptr">
9961 <inptr><struct>jvmtiCapabilities</struct></inptr>
9962 <description>
9963 points to the <jvmti/> capabilities to evaluate.
9964 </description>
9965 </param>
9966 <param id="time_impact_ptr">
9967 <outptr><jint/></outptr>
9968 <description>
9969 On return, points to the estimated percentage increase in
9970 run time if this capability was added.
9971 </description>
9972 </param>
9973 <param id="space_impact_ptr">
9974 <outptr><jint/></outptr>
9975 <description>
9976 On return, points to the estimated percentage increase in
9977 memory space used if this capability was added.
9978 </description>
9979 </param>
9980 </parameters>
9981 <errors>
9982 <error id="JVMTI_ERROR_NOT_AVAILABLE">
9983 The desired capabilities are not even potentially available.
9984 </error>
9985 </errors>
9986 </function>
9987 </elide>
9989 <function id="AddCapabilities" jkernel="yes" phase="onload" num="142">
9990 <synopsis>Add Capabilities</synopsis>
9991 <description>
9992 Set new capabilities by adding the capabilities
9993 whose values are set to one (<code>1</code>) in
9994 <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
9995 All previous capabilities are retained.
9996 Typically this function is used in the <code>OnLoad</code> function.
9997 Some virtual machines may allow a limited set of capabilities to be
9998 added in the live phase.
9999 <p/>
10000 See the
10001 <internallink id="capabilityExamples">Capability Examples</internallink>.
10002 </description>
10003 <origin>new</origin>
10004 <capabilities>
10005 </capabilities>
10006 <parameters>
10007 <param id="capabilities_ptr">
10008 <inptr><struct>jvmtiCapabilities</struct></inptr>
10009 <description>
10010 Points to the <jvmti/> capabilities to add.
10011 </description>
10012 </param>
10013 </parameters>
10014 <errors>
10015 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10016 The desired capabilities are not even potentially available.
10017 </error>
10018 </errors>
10019 </function>
10022 <function id="RelinquishCapabilities" phase="onload" num="143">
10023 <synopsis>Relinquish Capabilities</synopsis>
10024 <description>
10025 Relinquish the capabilities
10026 whose values are set to one (<code>1</code>) in
10027 <code>*</code><paramlink id="capabilities_ptr"></paramlink>.
10028 Some implementations may allow only one environment to have a capability
10029 (see the <internallink id="capability">capability introduction</internallink>).
10030 This function releases capabilities
10031 so that they may be used by other agents.
10032 All other capabilities are retained.
10033 The capability will no longer be present in <functionlink id="GetCapabilities"></functionlink>.
10034 Attempting to relinquish a capability that the agent does not possess is not an error.
10035 <issue>
10036 It is possible for the agent to be actively using capabilities
10037 which are being relinquished. For example, a thread is currently
10038 suspended and can_suspend is being relinquished or an event is currently
10039 enabled and can_generate_whatever is being relinquished.
10040 There are three possible ways we could spec this:
10041 <ul>
10042 <li>relinquish automatically releases them</li>
10043 <li>relinquish checks and returns some error code if held</li>
10044 <li>it is the agent's responsibility and it is not checked</li>
10045 </ul>
10046 One of these should be chosen.
10047 </issue>
10048 </description>
10049 <origin>new</origin>
10050 <capabilities>
10051 </capabilities>
10052 <parameters>
10053 <param id="capabilities_ptr">
10054 <inptr><struct>jvmtiCapabilities</struct></inptr>
10055 <description>
10056 Points to the <jvmti/> capabilities to relinquish.
10057 </description>
10058 </param>
10059 </parameters>
10060 <errors>
10061 </errors>
10062 </function>
10066 <function id="GetCapabilities" jkernel="yes" phase="any" num="89">
10067 <synopsis>Get Capabilities</synopsis>
10068 <description>
10069 Returns via <paramlink id="capabilities_ptr"></paramlink> the optional <jvmti/>
10070 features which this environment currently possesses.
10071 Each possessed capability is indicated by a one (<code>1</code>) in the
10072 corresponding field of the <internallink id="jvmtiCapabilities">capabilities
10073 structure</internallink>.
10074 An environment does not possess a capability unless it has been successfully added with
10075 <functionlink id="AddCapabilities"/>.
10076 An environment only loses possession of a capability if it has been relinquished with
10077 <functionlink id="RelinquishCapabilities"/>. Thus, this function returns the net result
10078 of the <code>AddCapabilities</code> and <code>RelinquishCapabilities</code> calls which
10079 have been made.
10080 <p/>
10081 See the
10082 <internallink id="capabilityExamples">Capability Examples</internallink>.
10083 </description>
10084 <origin>jvmdiClone</origin>
10085 <capabilities>
10086 </capabilities>
10087 <parameters>
10088 <param id="capabilities_ptr">
10089 <outptr><struct>jvmtiCapabilities</struct></outptr>
10090 <description>
10091 On return, points to the <jvmti/> capabilities.
10092 </description>
10093 </param>
10094 </parameters>
10095 <errors>
10096 </errors>
10097 </function>
10099 </category>
10102 <category id="timers" label="Timers">
10104 <intro>
10105 These functions provide timing information.
10106 The resolution at which the time is updated is not specified.
10107 They provides nanosecond precision, but not necessarily nanosecond accuracy.
10108 Details about the timers, such as their maximum values, can be accessed with
10109 the timer information functions.
10110 </intro>
10112 <typedef id="jvmtiTimerInfo" label="Timer Info">
10113 <description>
10114 The information function for each timer returns this data structure.
10115 </description>
10116 <field id="max_value">
10117 <jlong/>
10118 <description>
10119 The maximum value the timer can reach.
10120 After this value is reached the timer wraps back to zero.
10121 This is an unsigned value. If tested or printed as a jlong (signed value)
10122 it may appear to be a negative number.
10123 </description>
10124 </field>
10125 <field id="may_skip_forward">
10126 <jboolean/>
10127 <description>
10128 If true, the timer can be externally adjusted and as a result skip forward.
10129 If false, the timer value will never increase faster than real time.
10130 </description>
10131 </field>
10132 <field id="may_skip_backward">
10133 <jboolean/>
10134 <description>
10135 If true, the timer can be externally adjusted and as a result skip backward.
10136 If false, the timer value will be monotonically increasing.
10137 </description>
10138 </field>
10139 <field id="kind">
10140 <enum>jvmtiTimerKind</enum>
10141 <description>
10142 The kind of timer.
10143 On a platform that does not distinguish between user and system time, <datalink
10144 id="JVMTI_TIMER_TOTAL_CPU"><code>JVMTI_TIMER_TOTAL_CPU</code></datalink>
10145 is returned.
10146 </description>
10147 </field>
10148 <field id="reserved1">
10149 <jlong/>
10150 <description>
10151 Reserved for future use.
10152 </description>
10153 </field>
10154 <field id="reserved2">
10155 <jlong/>
10156 <description>
10157 Reserved for future use.
10158 </description>
10159 </field>
10160 </typedef>
10162 <intro>
10163 Where the timer kind is --
10165 <constants id="jvmtiTimerKind" label="Timer Kinds" kind="enum">
10166 <constant id="JVMTI_TIMER_USER_CPU" num="30">
10167 CPU time that a thread is in user mode.
10168 </constant>
10169 <constant id="JVMTI_TIMER_TOTAL_CPU" num="31">
10170 CPU time that a thread is in user or system mode.
10171 </constant>
10172 <constant id="JVMTI_TIMER_ELAPSED" num="32">
10173 Elapsed time.
10174 </constant>
10175 </constants>
10176 </intro>
10178 <function id="GetCurrentThreadCpuTimerInfo" callbacksafe="safe" impl="innative notrace" phase="start" num="134">
10179 <synopsis>Get Current Thread CPU Timer Information</synopsis>
10180 <description>
10181 Get information about the
10182 <functionlink id="GetCurrentThreadCpuTime"/> timer.
10183 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10184 are filled in with details about the timer.
10185 This information is specific to the platform and the implementation of
10186 <functionlink id="GetCurrentThreadCpuTime"/> and thus
10187 does not vary by thread nor does it vary
10188 during a particular invocation of the VM.
10189 <p/>
10190 Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10191 and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10192 returned by <code>GetCurrentThreadCpuTimerInfo</code>
10193 and <functionlink id="GetThreadCpuTimerInfo"/>
10194 may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10195 </description>
10196 <origin>new</origin>
10197 <capabilities>
10198 <required id="can_get_current_thread_cpu_time">
10199 Can get current thread CPU time.
10200 </required>
10201 </capabilities>
10202 <parameters>
10203 <param id="info_ptr">
10204 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10205 <description>
10206 On return, filled with information describing the time
10207 returned by <functionlink id="GetCurrentThreadCpuTime"/>.
10208 </description>
10209 </param>
10210 </parameters>
10211 <errors>
10212 </errors>
10213 </function>
10215 <function id="GetCurrentThreadCpuTime" callbacksafe="safe" impl="innative notrace" phase="start" num="135">
10216 <synopsis>Get Current Thread CPU Time</synopsis>
10217 <description>
10218 Return the CPU time utilized by the current thread.
10219 <p/>
10220 Note that the <functionlink id="GetThreadCpuTime"/>
10221 function provides CPU time for any thread, including
10222 the current thread. <code>GetCurrentThreadCpuTime</code>
10223 exists to support platforms which cannot
10224 supply CPU time for threads other than the current
10225 thread or which have more accurate information for
10226 the current thread (see
10227 <functionlink id="GetCurrentThreadCpuTimerInfo"/> vs
10228 <functionlink id="GetThreadCpuTimerInfo"/>).
10229 On many platforms this call will be equivalent to:
10230 <example>
10231 GetThreadCpuTime(env, NULL, nanos_ptr)
10232 </example>
10233 </description>
10234 <origin>new</origin>
10235 <capabilities>
10236 <required id="can_get_current_thread_cpu_time">
10237 Can get current thread CPU time.
10238 <p/>
10239 If this capability is enabled after threads have started,
10240 the implementation may choose any time up
10241 to and including the time that the capability is enabled
10242 as the point where CPU time collection starts.
10243 <p/>
10244 This capability must be potentially available on any
10245 platform where
10246 <internallink id="jvmtiCapabilities.can_get_thread_cpu_time"><code>can_get_thread_cpu_time</code></internallink>
10247 is potentially available.
10248 </required>
10249 </capabilities>
10250 <parameters>
10251 <param id="nanos_ptr">
10252 <outptr><jlong/></outptr>
10253 <description>
10254 On return, points to the CPU time used by this thread
10255 in nanoseconds.
10256 This is an unsigned value. If tested or printed as a jlong (signed value)
10257 it may appear to be a negative number.
10258 </description>
10259 </param>
10260 </parameters>
10261 <errors>
10262 </errors>
10263 </function>
10265 <function id="GetThreadCpuTimerInfo" num="136">
10266 <synopsis>Get Thread CPU Timer Information</synopsis>
10267 <description>
10268 Get information about the
10269 <functionlink id="GetThreadCpuTime"/> timer.
10270 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10271 are filled in with details about the timer.
10272 This information is specific to the platform and the implementation of
10273 <functionlink id="GetThreadCpuTime"/> and thus
10274 does not vary by thread nor does it vary
10275 during a particular invocation of the VM.
10276 <p/>
10277 Note that the implementations of <functionlink id="GetCurrentThreadCpuTime"/>
10278 and <functionlink id="GetThreadCpuTime"/> may differ, and thus the values
10279 returned by <functionlink id="GetCurrentThreadCpuTimerInfo"/>
10280 and <code>GetThreadCpuTimerInfo</code>
10281 may differ -- see <functionlink id="GetCurrentThreadCpuTime"/> for more information.
10282 </description>
10283 <origin>new</origin>
10284 <capabilities>
10285 <required id="can_get_thread_cpu_time">
10286 Can get thread CPU time.
10287 </required>
10288 </capabilities>
10289 <parameters>
10290 <param id="info_ptr">
10291 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10292 <description>
10293 On return, filled with information describing the time
10294 returned by <functionlink id="GetThreadCpuTime"/>.
10295 </description>
10296 </param>
10297 </parameters>
10298 <errors>
10299 </errors>
10300 </function>
10302 <function id="GetThreadCpuTime" num="137">
10303 <synopsis>Get Thread CPU Time</synopsis>
10304 <description>
10305 Return the CPU time utilized by the specified thread.
10306 <p/>
10307 Get information about this timer with
10308 <functionlink id="GetThreadCpuTimerInfo"/>.
10309 </description>
10310 <origin>new</origin>
10311 <capabilities>
10312 <required id="can_get_thread_cpu_time">
10313 Can get thread CPU time.
10314 <p/>
10315 If this capability is enabled after threads have started,
10316 the implementation may choose any time up
10317 to and including the time that the capability is enabled
10318 as the point where CPU time collection starts.
10319 </required>
10320 </capabilities>
10321 <parameters>
10322 <param id="thread">
10323 <jthread null="current"/>
10324 <description>
10325 The thread to query.
10326 </description>
10327 </param>
10328 <param id="nanos_ptr">
10329 <outptr><jlong/></outptr>
10330 <description>
10331 On return, points to the CPU time used by the specified thread
10332 in nanoseconds.
10333 This is an unsigned value. If tested or printed as a jlong (signed value)
10334 it may appear to be a negative number.
10335 </description>
10336 </param>
10337 </parameters>
10338 <errors>
10339 </errors>
10340 </function>
10342 <function id="GetTimerInfo" phase="any" callbacksafe="safe" num="138">
10343 <synopsis>Get Timer Information</synopsis>
10344 <description>
10345 Get information about the
10346 <functionlink id="GetTime"/> timer.
10347 The fields of the <datalink id="jvmtiTimerInfo"/> structure
10348 are filled in with details about the timer.
10349 This information will not change during a particular invocation of the VM.
10350 </description>
10351 <origin>new</origin>
10352 <capabilities>
10353 </capabilities>
10354 <parameters>
10355 <param id="info_ptr">
10356 <outptr><struct>jvmtiTimerInfo</struct></outptr>
10357 <description>
10358 On return, filled with information describing the time
10359 returned by <functionlink id="GetTime"/>.
10360 </description>
10361 </param>
10362 </parameters>
10363 <errors>
10364 </errors>
10365 </function>
10367 <function id="GetTime" phase="any" callbacksafe="safe" num="139">
10368 <synopsis>Get Time</synopsis>
10369 <description>
10370 Return the current value of the system timer, in nanoseconds.
10371 <p/>
10372 The value returned represents nanoseconds since some fixed but
10373 arbitrary time (perhaps in the future, so values may be
10374 negative). This function provides nanosecond precision, but not
10375 necessarily nanosecond accuracy. No guarantees are made about
10376 how frequently values change.
10377 <p/>
10378 Get information about this timer with
10379 <functionlink id="GetTimerInfo"/>.
10380 </description>
10381 <origin>new</origin>
10382 <capabilities>
10383 </capabilities>
10384 <parameters>
10385 <param id="nanos_ptr">
10386 <outptr><jlong/></outptr>
10387 <description>
10388 On return, points to the time in nanoseconds.
10389 This is an unsigned value. If tested or printed as a jlong (signed value)
10390 it may appear to be a negative number.
10391 </description>
10392 </param>
10393 </parameters>
10394 <errors>
10395 </errors>
10396 </function>
10398 <function id="GetAvailableProcessors" phase="any" num="144">
10399 <synopsis>Get Available Processors</synopsis>
10400 <description>
10401 Returns the number of processors available to the Java virtual machine.
10402 <p/>
10403 This value may change during a particular invocation of the virtual machine.
10404 Applications that are sensitive to the number of available processors should
10405 therefore occasionally poll this property.
10406 </description>
10407 <origin>new</origin>
10408 <capabilities>
10409 </capabilities>
10410 <parameters>
10411 <param id="processor_count_ptr">
10412 <outptr><jint/></outptr>
10413 <description>
10414 On return, points to the maximum number of processors available to the
10415 virtual machine; never smaller than one.
10416 </description>
10417 </param>
10418 </parameters>
10419 <errors>
10420 </errors>
10421 </function>
10423 </category>
10426 <category id="classLoaderSearch" label="Class Loader Search">
10428 <intro>
10429 These functions allow the agent to add to the locations that a class loader searches for a class.
10430 This is useful for installing instrumentation under the correct class loader.
10431 </intro>
10433 <function id="AddToBootstrapClassLoaderSearch" jkernel="yes" phase="onload" num="149">
10434 <synopsis>Add To Bootstrap Class Loader Search</synopsis>
10435 <description>
10436 This function can be used to cause instrumentation classes to be defined by the
10437 bootstrap class loader. See <vmspec chapter="5.3.1"/>.
10438 After the bootstrap
10439 class loader unsuccessfully searches for a class, the specified platform-dependent
10440 search path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in
10441 the <paramlink id="segment"/>. This function may be called multiple times to add multiple segments,
10442 the segments will be searched in the order that this function was called.
10443 <p/>
10444 In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
10445 search path segment to be searched after the bootstrap class loader unsuccessfully searches
10446 for a class. The segment is typically a directory or JAR file.
10447 <p/>
10448 In the live phase the <paramlink id="segment"/> may be used to specify any platform-dependent
10449 path to a <externallink id="http://java.sun.com/javase/6/docs/guide/jar/jar.html">
10450 JAR file</externallink>. The agent should take care that the JAR file does not
10451 contain any classes or resources other than those to be defined by the bootstrap
10452 class loader for the purposes of instrumentation.
10453 <p/>
10454 <vmspec/> specifies that a subsequent attempt to resolve a symbolic
10455 reference that the Java virtual machine has previously unsuccessfully attempted
10456 to resolve always fails with the same error that was thrown as a result of the
10457 initial resolution attempt. Consequently, if the JAR file contains an entry
10458 that corresponds to a class for which the Java virtual machine has
10459 unsuccessfully attempted to resolve a reference, then subsequent attempts to
10460 resolve that reference will fail with the same error as the initial attempt.
10461 </description>
10462 <origin>new</origin>
10463 <capabilities>
10464 </capabilities>
10465 <parameters>
10466 <param id="segment">
10467 <inbuf><char/></inbuf>
10468 <description>
10469 The platform-dependent search path segment, encoded as a
10470 <internallink id="mUTF">modified UTF-8</internallink> string.
10471 </description>
10472 </param>
10473 </parameters>
10474 <errors>
10475 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
10476 <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
10477 existing JAR file is an invalid path.
10478 </error>
10479 </errors>
10480 </function>
10482 <function id="AddToSystemClassLoaderSearch" jkernel="yes" phase="onload" num="151" since="1.1">
10483 <synopsis>Add To System Class Loader Search</synopsis>
10484 <description>
10485 This function can be used to cause instrumentation classes to be
10486 defined by the system class loader. See <vmspec chapter="5.3.2"/>.
10487 After the class loader unsuccessfully searches for a class, the specified platform-dependent search
10488 path <paramlink id="segment"/> will be searched as well. Only one segment may be specified in the
10489 <paramlink id="segment"/>. This function may be called multiple times to add multiple segments, the
10490 segments will be searched in the order that this function was called.
10491 <p/>
10492 In the <code>OnLoad</code> phase the function may be used to specify any platform-dependent
10493 search path segment to be searched after the system class loader unsuccessfully searches
10494 for a class. The segment is typically a directory or JAR file.
10495 <p/>
10496 In the live phase the <paramlink id="segment"/> is a platform-dependent path to a <externallink
10497 id="http://java.sun.com/javase/6/docs/guide/jar/jar.html">JAR file</externallink> to be
10498 searched after the system class loader unsuccessfully searches for a class. The agent should
10499 take care that the JAR file does not contain any classes or resources other than those to be
10500 defined by the system class loader for the purposes of instrumentation.
10501 <p/>
10502 In the live phase the system class loader supports adding a JAR file to be searched if
10503 the system class loader implements a method name <code>appendToClassPathForInstrumentation</code>
10504 which takes a single parameter of type <code>java.lang.String</code>. The method is not required
10505 to have <code>public</code> access.
10506 <p/>
10507 <vmspec/> specifies that a subsequent attempt to resolve a symbolic
10508 reference that the Java virtual machine has previously unsuccessfully attempted
10509 to resolve always fails with the same error that was thrown as a result of the
10510 initial resolution attempt. Consequently, if the JAR file contains an entry
10511 that corresponds to a class for which the Java virtual machine has
10512 unsuccessfully attempted to resolve a reference, then subsequent attempts to
10513 resolve that reference will fail with the same error as the initial attempt.
10514 </description>
10515 <origin>new</origin>
10516 <capabilities>
10517 </capabilities>
10518 <parameters>
10519 <param id="segment">
10520 <inbuf><char/></inbuf>
10521 <description>
10522 The platform-dependent search path segment, encoded as a
10523 <internallink id="mUTF">modified UTF-8</internallink> string.
10524 </description>
10525 </param>
10526 </parameters>
10527 <errors>
10528 <error id="JVMTI_ERROR_ILLEGAL_ARGUMENT">
10529 <paramlink id="segment"/> is an invalid path. In the live phase, anything other than an
10530 existing JAR file is an invalid path.
10531 </error>
10532 <error id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED">
10533 Operation not supported by the system class loader.
10534 </error>
10535 </errors>
10536 </function>
10538 </category>
10541 <category id="props" label="System Properties">
10543 <intro>
10544 These functions get and set system properties.
10545 </intro>
10547 <function id="GetSystemProperties" phase="onload" num="130">
10548 <synopsis>Get System Properties</synopsis>
10549 <description>
10550 The list of VM system property keys which may be used with
10551 <functionlink id="GetSystemProperty"/> is returned.
10552 It is strongly recommended that virtual machines provide the
10553 following property keys:
10554 <ul>
10555 <li><code>java.vm.vendor</code></li>
10556 <li><code>java.vm.version</code></li>
10557 <li><code>java.vm.name</code></li>
10558 <li><code>java.vm.info</code></li>
10559 <li><code>java.library.path</code></li>
10560 <li><code>java.class.path</code></li>
10561 </ul>
10562 Provides access to system properties defined by and used
10563 by the VM.
10564 Properties set on the command-line are included.
10565 This allows getting and setting of these properties
10566 before the VM even begins executing bytecodes.
10567 Since this is a VM view of system properties, the set of available
10568 properties will usually be different than that
10569 in <code>java.lang.System.getProperties</code>.
10570 JNI method invocation may be used to access
10571 <code>java.lang.System.getProperties</code>.
10572 <p/>
10573 The set of properties may grow during execution.
10574 </description>
10575 <origin>new</origin>
10576 <capabilities>
10577 </capabilities>
10578 <parameters>
10579 <param id="count_ptr">
10580 <outptr><jint/></outptr>
10581 <description>
10582 On return, points to the number of property keys returned.
10583 </description>
10584 </param>
10585 <param id="property_ptr">
10586 <allocallocbuf outcount="count_ptr"><char/></allocallocbuf>
10587 <description>
10588 On return, points to an array of property keys, encoded as
10589 <internallink id="mUTF">modified UTF-8</internallink> strings.
10590 </description>
10591 </param>
10592 </parameters>
10593 <errors>
10594 </errors>
10595 </function>
10597 <function id="GetSystemProperty" phase="onload" num="131">
10598 <synopsis>Get System Property</synopsis>
10599 <description>
10600 Return a VM system property value given the property key.
10601 <p/>
10602 The function <functionlink id="GetSystemProperties"/>
10603 returns the set of property keys which may be used.
10604 The properties which can be retrieved may grow during
10605 execution.
10606 <p/>
10607 Since this is a VM view of system properties, the values
10608 of properties may differ from that returned by
10609 <code>java.lang.System.getProperty(String)</code>.
10610 A typical VM might copy the values of the VM system
10611 properties into the <code>Properties</code> held by
10612 <code>java.lang.System</code> during the initialization
10613 of that class. Thereafter any changes to the VM system
10614 properties (with <functionlink id="SetSystemProperty"/>)
10615 or the <code>java.lang.System</code> system properties
10616 (with <code>java.lang.System.setProperty(String,String)</code>)
10617 would cause the values to diverge.
10618 JNI method invocation may be used to access
10619 <code>java.lang.System.getProperty(String)</code>.
10620 </description>
10621 <origin>new</origin>
10622 <capabilities>
10623 </capabilities>
10624 <parameters>
10625 <param id="property">
10626 <inbuf><char/></inbuf>
10627 <description>
10628 The key of the property to retrieve, encoded as a
10629 <internallink id="mUTF">modified UTF-8</internallink> string.
10630 </description>
10631 </param>
10632 <param id="value_ptr">
10633 <allocbuf><char/></allocbuf>
10634 <description>
10635 On return, points to the property value, encoded as a
10636 <internallink id="mUTF">modified UTF-8</internallink> string.
10637 </description>
10638 </param>
10639 </parameters>
10640 <errors>
10641 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10642 This property is not available.
10643 Use <functionlink id="GetSystemProperties"/> to find available properties.
10644 </error>
10645 </errors>
10646 </function>
10648 <function id="SetSystemProperty" phase="onloadOnly" num="132">
10649 <synopsis>Set System Property</synopsis>
10650 <description>
10651 Set a VM system property value.
10652 <p/>
10653 The function <functionlink id="GetSystemProperties"/>
10654 returns the set of property keys, some of these may be settable.
10655 See <functionlink id="GetSystemProperty"/>.
10656 </description>
10657 <origin>new</origin>
10658 <capabilities>
10659 </capabilities>
10660 <parameters>
10661 <param id="property">
10662 <inbuf><char/></inbuf>
10663 <description>
10664 The key of the property, encoded as a
10665 <internallink id="mUTF">modified UTF-8</internallink> string.
10666 </description>
10667 </param>
10668 <param id="value_ptr">
10669 <inbuf>
10670 <char/>
10671 <nullok>
10672 do not set the value, but return <errorlink id="JVMTI_ERROR_NOT_AVAILABLE"/>
10673 if the property is not writeable
10674 </nullok>
10675 </inbuf>
10676 <description>
10677 The property value to set, encoded as a
10678 <internallink id="mUTF">modified UTF-8</internallink> string.
10679 </description>
10680 </param>
10681 </parameters>
10682 <errors>
10683 <error id="JVMTI_ERROR_NOT_AVAILABLE">
10684 This property is not available or is not writeable.
10685 </error>
10686 </errors>
10687 </function>
10689 </category>
10691 <category id="general" label="General">
10693 <intro>
10694 </intro>
10696 <function id="GetPhase" jkernel="yes" phase="any" num="133">
10697 <synopsis>Get Phase</synopsis>
10698 <description>
10699 Return the current phase of VM execution.
10700 The phases proceed in sequence:
10701 <constants id="jvmtiPhase" label="Phases of execution" kind="enum">
10702 <constant id="JVMTI_PHASE_ONLOAD" num="1">
10703 <code>OnLoad</code> phase: while in the
10704 <internallink id="onload"><code>Agent_OnLoad</code></internallink> function.
10705 </constant>
10706 <constant id="JVMTI_PHASE_PRIMORDIAL" num="2">
10707 Primordial phase: between return from <code>Agent_OnLoad</code> and the
10708 <code>VMStart</code> event.
10709 </constant>
10710 <constant id="JVMTI_PHASE_START" num="6">
10711 Start phase: when the <eventlink id="VMStart"><code>VMStart</code></eventlink> event
10712 is sent and until the <code>VMInit</code> event is sent.
10713 </constant>
10714 <constant id="JVMTI_PHASE_LIVE" num="4">
10715 Live phase: when the <eventlink id="VMInit"><code>VMInit</code></eventlink> event is sent
10716 and until the <eventlink id="VMDeath"></eventlink> event returns.
10717 </constant>
10718 <constant id="JVMTI_PHASE_DEAD" num="8">
10719 Dead phase: after the <eventlink id="VMDeath"></eventlink> event returns or after
10720 start-up failure.
10721 </constant>
10722 </constants>
10723 In the case of start-up failure the VM will proceed directly to the dead
10724 phase skipping intermediate phases and neither a <code>VMInit</code> nor
10725 <code>VMDeath</code> event will be sent.
10726 <p/>
10727 Most <jvmti/> functions operate only in the live phase.
10728 The following functions operate in either the <code>OnLoad</code> or live phases:
10729 <functionphaselist phase="onload"/>
10730 The following functions operate in only the <code>OnLoad</code> phase:
10731 <functionphaselist phase="onloadOnly"/>
10732 The following functions operate in the start or live phases:
10733 <functionphaselist phase="start"/>
10734 The following functions operate in any phase:
10735 <functionphaselist phase="any"/>
10736 JNI functions (except the Invocation API) must only be used in the start or live phases.
10737 <p/>
10738 Most <jvmti/> events are sent only in the live phase.
10739 The following events operate in others phases:
10740 <eventphaselist phase="start"/>
10741 <eventphaselist phase="any"/>
10742 </description>
10743 <origin>new</origin>
10744 <capabilities>
10745 </capabilities>
10746 <parameters>
10747 <param id="phase_ptr">
10748 <outptr><enum>jvmtiPhase</enum></outptr>
10749 <description>
10750 On return, points to the phase.
10751 </description>
10752 </param>
10753 </parameters>
10754 <errors>
10755 </errors>
10756 </function>
10758 <function id="DisposeEnvironment" jkernel="yes" phase="any" num="127">
10759 <synopsis>Dispose Environment</synopsis>
10760 <description>
10761 Shutdown a <jvmti/> connection created with JNI <code>GetEnv</code>
10762 (see <internallink id="environments"><jvmti/> Environments</internallink>).
10763 Dispose of any resources held by the environment.
10764 <issue>
10765 What resources are reclaimed? What is undone?
10766 Breakpoints,watchpoints removed?
10767 </issue>
10768 Threads suspended by this environment are not resumed by this call,
10769 this must be done explicitly by the agent.
10770 Memory allocated by this environment via calls to <jvmti/> functions
10771 is not released, this can be done explicitly by the agent
10772 by calling <functionlink id="Deallocate"/>.
10773 Raw monitors created by this environment are not destroyed,
10774 this can be done explicitly by the agent
10775 by calling <functionlink id="DestroyRawMonitor"/>.
10776 The state of threads waiting on raw monitors created by this environment
10777 are not affected.
10778 <p/>
10779 Any <functionlink id="SetNativeMethodPrefix">native method
10780 prefixes</functionlink> for this environment will be unset;
10781 the agent must remove any prefixed native methods before
10782 dispose is called.
10783 <p/>
10784 Any <internallink id="capability">capabilities</internallink>
10785 held by this environment are relinquished.
10786 <p/>
10787 Events enabled by this environment will no longer be sent, however
10788 event handlers currently running will continue to run. Caution must
10789 be exercised in the design of event handlers whose environment may
10790 be disposed and thus become invalid during their execution.
10791 <p/>
10792 This environment may not be used after this call.
10793 This call returns to the caller.
10794 </description>
10795 <origin>new</origin>
10796 <capabilities>
10797 </capabilities>
10798 <parameters>
10799 </parameters>
10800 <errors>
10801 </errors>
10802 </function>
10804 <function id="SetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="148">
10805 <synopsis>Set Environment Local Storage</synopsis>
10806 <description>
10807 The VM stores a pointer value associated with each environment.
10808 This pointer value is called <i>environment-local storage</i>.
10809 This value is <code>NULL</code> unless set with this function.
10810 Agents can allocate memory in which they store environment specific
10811 information. By setting environment-local storage it can then be
10812 accessed with
10813 <functionlink id="GetEnvironmentLocalStorage"></functionlink>.
10814 <p/>
10815 Called by the agent to set the value of the <jvmti/>
10816 environment-local storage. <jvmti/> supplies to the agent a pointer-size
10817 environment-local storage that can be used to record per-environment
10818 information.
10819 </description>
10820 <origin>new</origin>
10821 <capabilities>
10822 </capabilities>
10823 <parameters>
10824 <param id="data">
10825 <inbuf>
10826 <void/>
10827 <nullok>value is set to <code>NULL</code></nullok>
10828 </inbuf>
10829 <description>
10830 The value to be entered into the environment-local storage.
10831 </description>
10832 </param>
10833 </parameters>
10834 <errors>
10835 </errors>
10836 </function>
10838 <function id="GetEnvironmentLocalStorage" jkernel="yes" phase="any" callbacksafe="safe" impl="innative notrace" num="147">
10839 <synopsis>Get Environment Local Storage</synopsis>
10840 <description>
10841 Called by the agent to get the value of the <jvmti/> environment-local
10842 storage.
10843 </description>
10844 <origin>new</origin>
10845 <capabilities>
10846 </capabilities>
10847 <parameters>
10848 <param id="data_ptr">
10849 <agentbuf><void/></agentbuf>
10850 <description>
10851 Pointer through which the value of the environment local
10852 storage is returned.
10853 If environment-local storage has not been set with
10854 <functionlink id="SetEnvironmentLocalStorage"></functionlink> returned
10855 pointer is <code>NULL</code>.
10856 </description>
10857 </param>
10858 </parameters>
10859 <errors>
10860 </errors>
10861 </function>
10863 <function id="GetVersionNumber" jkernel="yes" phase="any" num="88">
10864 <synopsis>Get Version Number</synopsis>
10865 <description>
10866 Return the <jvmti/> version via <code>version_ptr</code>.
10867 The return value is the version identifier.
10868 The version identifier includes major, minor and micro
10869 version as well as the interface type.
10870 <constants id="jvmtiVersionInterfaceTypes" label="Version Interface Types" kind="bits">
10871 <constant id="JVMTI_VERSION_INTERFACE_JNI" num="0x00000000">
10872 Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for JNI.
10873 </constant>
10874 <constant id="JVMTI_VERSION_INTERFACE_JVMTI" num="0x30000000">
10875 Value of <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> for <jvmti/>.
10876 </constant>
10877 </constants>
10878 <constants id="jvmtiVersionMasks" label="Version Masks" kind="bits">
10879 <constant id="JVMTI_VERSION_MASK_INTERFACE_TYPE" num="0x70000000">
10880 Mask to extract interface type.
10881 The value of the version returned by this function masked with
10882 <code>JVMTI_VERSION_MASK_INTERFACE_TYPE</code> is always
10883 <code>JVMTI_VERSION_INTERFACE_JVMTI</code>
10884 since this is a <jvmti/> function.
10885 </constant>
10886 <constant id="JVMTI_VERSION_MASK_MAJOR" num="0x0FFF0000">
10887 Mask to extract major version number.
10888 </constant>
10889 <constant id="JVMTI_VERSION_MASK_MINOR" num="0x0000FF00">
10890 Mask to extract minor version number.
10891 </constant>
10892 <constant id="JVMTI_VERSION_MASK_MICRO" num="0x000000FF">
10893 Mask to extract micro version number.
10894 </constant>
10895 </constants>
10896 <constants id="jvmtiVersionShifts" label="Version Shifts" kind="bits">
10897 <constant id="JVMTI_VERSION_SHIFT_MAJOR" num="16">
10898 Shift to extract major version number.
10899 </constant>
10900 <constant id="JVMTI_VERSION_SHIFT_MINOR" num="8">
10901 Shift to extract minor version number.
10902 </constant>
10903 <constant id="JVMTI_VERSION_SHIFT_MICRO" num="0">
10904 Shift to extract micro version number.
10905 </constant>
10906 </constants>
10907 </description>
10908 <origin>jvmdi</origin>
10909 <capabilities>
10910 </capabilities>
10911 <parameters>
10912 <param id="version_ptr">
10913 <outptr><jint/></outptr>
10914 <description>
10915 On return, points to the <jvmti/> version.
10916 </description>
10917 </param>
10918 </parameters>
10919 <errors>
10920 </errors>
10921 </function>
10924 <function id="GetErrorName" phase="any" num="128">
10925 <synopsis>Get Error Name</synopsis>
10926 <description>
10927 Return the symbolic name for an
10928 <internallink id="ErrorSection">error code</internallink>.
10929 <p/>
10930 For example
10931 <code>GetErrorName(env, JVMTI_ERROR_NONE, &err_name)</code>
10932 would return in <code>err_name</code> the string
10933 <code>"JVMTI_ERROR_NONE"</code>.
10934 </description>
10935 <origin>new</origin>
10936 <capabilities>
10937 </capabilities>
10938 <parameters>
10939 <param id="error">
10940 <enum>jvmtiError</enum>
10941 <description>
10942 The error code.
10943 </description>
10944 </param>
10945 <param id="name_ptr">
10946 <allocbuf><char/></allocbuf>
10947 <description>
10948 On return, points to the error name.
10949 The name is encoded as a
10950 <internallink id="mUTF">modified UTF-8</internallink> string,
10951 but is restricted to the ASCII subset.
10952 </description>
10953 </param>
10954 </parameters>
10955 <errors>
10956 </errors>
10957 </function>
10959 <function id="SetVerboseFlag" phase="any" num="150">
10960 <synopsis>Set Verbose Flag</synopsis>
10961 <description>
10962 <constants id="jvmtiVerboseFlag" label="Verbose Flag Enumeration" kind="enum">
10963 <constant id="JVMTI_VERBOSE_OTHER" num="0">
10964 Verbose output other than the below.
10965 </constant>
10966 <constant id="JVMTI_VERBOSE_GC" num="1">
10967 Verbose garbage collector output, like that specified with <code>-verbose:gc</code>.
10968 </constant>
10969 <constant id="JVMTI_VERBOSE_CLASS" num="2">
10970 Verbose class loading output, like that specified with <code>-verbose:class</code>.
10971 </constant>
10972 <constant id="JVMTI_VERBOSE_JNI" num="4">
10973 Verbose JNI output, like that specified with <code>-verbose:jni</code>.
10974 </constant>
10975 </constants>
10976 Control verbose output.
10977 This is the output which typically is sent to <code>stderr</code>.
10978 </description>
10979 <origin>new</origin>
10980 <capabilities>
10981 </capabilities>
10982 <parameters>
10983 <param id="flag">
10984 <enum>jvmtiVerboseFlag</enum>
10985 <description>
10986 Which verbose flag to set.
10987 </description>
10988 </param>
10989 <param id="value">
10990 <jboolean/>
10991 <description>
10992 New value of the flag.
10993 </description>
10994 </param>
10995 </parameters>
10996 <errors>
10997 </errors>
10998 </function>
11001 <function id="GetJLocationFormat" phase="any" num="129">
11002 <synopsis>Get JLocation Format</synopsis>
11003 <description>
11004 Although the greatest functionality is achieved with location information
11005 referencing the virtual machine bytecode index, the definition of
11006 <code>jlocation</code> has intentionally been left unconstrained to allow VM
11007 implementations that do not have this information.
11008 <p/>
11009 This function describes the representation of <code>jlocation</code> used in this VM.
11010 If the returned format is <datalink id="JVMTI_JLOCATION_JVMBCI"></datalink>,
11011 <code>jlocation</code>s can
11012 be used as in indices into the array returned by
11013 <functionlink id="GetBytecodes"></functionlink>.
11014 <constants id="jvmtiJlocationFormat" label="JLocation Format Enumeration" kind="enum">
11015 <constant id="JVMTI_JLOCATION_JVMBCI" num="1">
11016 <code>jlocation</code> values represent virtual machine
11017 bytecode indices--that is, offsets into the
11018 virtual machine code for a method.
11019 </constant>
11020 <constant id="JVMTI_JLOCATION_MACHINEPC" num="2">
11021 <code>jlocation</code> values represent native machine
11022 program counter values.
11023 </constant>
11024 <constant id="JVMTI_JLOCATION_OTHER" num="0">
11025 <code>jlocation</code> values have some other representation.
11026 </constant>
11027 </constants>
11028 </description>
11029 <origin>new</origin>
11030 <capabilities>
11031 </capabilities>
11032 <parameters>
11033 <param id="format_ptr">
11034 <outptr><enum>jvmtiJlocationFormat</enum></outptr>
11035 <description>
11036 On return, points to the format identifier for <code>jlocation</code> values.
11037 </description>
11038 </param>
11039 </parameters>
11040 <errors>
11041 </errors>
11042 </function>
11044 </category>
11046 </functionsection>
11048 <errorsection label="Error Reference">
11049 <intro>
11050 Every <jvmti/> function returns a <b><code>jvmtiError</code></b> error code.
11051 <p/>
11052 It is the responsibility of the agent to call <jvmti/> functions with
11053 valid parameters and in the proper context (calling thread is attached,
11054 phase is correct, etc.).
11055 Detecting some error conditions may be difficult, inefficient, or
11056 impossible for an implementation.
11057 The errors listed in
11058 <internallink id="reqerrors">Function Specific Required Errors</internallink>
11059 must be detected by the implementation.
11060 All other errors represent the recommended response to the error
11061 condition.
11062 </intro>
11064 <errorcategory id="universal-error" label="Universal Errors">
11065 <intro>
11066 The following errors may be returned by any function
11067 </intro>
11069 <errorid id="JVMTI_ERROR_NONE" num="0">
11070 No error has occurred. This is the error code that is returned
11071 on successful completion of the function.
11072 </errorid>
11073 <errorid id="JVMTI_ERROR_NULL_POINTER" num="100">
11074 Pointer is unexpectedly <code>NULL</code>.
11075 </errorid>
11076 <errorid id="JVMTI_ERROR_OUT_OF_MEMORY" num="110">
11077 The function attempted to allocate memory and no more memory was
11078 available for allocation.
11079 </errorid>
11080 <errorid id="JVMTI_ERROR_ACCESS_DENIED" num="111">
11081 The desired functionality has not been enabled in this virtual machine.
11082 </errorid>
11083 <errorid id="JVMTI_ERROR_UNATTACHED_THREAD" num="115">
11084 The thread being used to call this function is not attached
11085 to the virtual machine. Calls must be made from attached threads.
11086 See <code>AttachCurrentThread</code> in the JNI invocation API.
11087 </errorid>
11088 <errorid id="JVMTI_ERROR_INVALID_ENVIRONMENT" num="116">
11089 The <jvmti/> environment provided is no longer connected or is
11090 not an environment.
11091 </errorid>
11092 <errorid id="JVMTI_ERROR_WRONG_PHASE" num="112">
11093 The desired functionality is not available in the current
11094 <functionlink id="GetPhase">phase</functionlink>.
11095 Always returned if the virtual machine has completed running.
11096 </errorid>
11097 <errorid id="JVMTI_ERROR_INTERNAL" num="113">
11098 An unexpected internal error has occurred.
11099 </errorid>
11100 </errorcategory>
11102 <errorcategory id="reqerrors" label="Function Specific Required Errors">
11103 <intro>
11104 The following errors are returned by some <jvmti/> functions and must
11105 be returned by the implementation when the condition occurs.
11106 </intro>
11108 <errorid id="JVMTI_ERROR_INVALID_PRIORITY" num="12">
11109 Invalid priority.
11110 </errorid>
11111 <errorid id="JVMTI_ERROR_THREAD_NOT_SUSPENDED" num="13">
11112 Thread was not suspended.
11113 </errorid>
11114 <errorid id="JVMTI_ERROR_THREAD_SUSPENDED" num="14">
11115 Thread already suspended.
11116 </errorid>
11117 <errorid id="JVMTI_ERROR_THREAD_NOT_ALIVE" num="15">
11118 This operation requires the thread to be alive--that is,
11119 it must be started and not yet have died.
11120 </errorid>
11121 <errorid id="JVMTI_ERROR_CLASS_NOT_PREPARED" num="22">
11122 The class has been loaded but not yet prepared.
11123 </errorid>
11124 <errorid id="JVMTI_ERROR_NO_MORE_FRAMES" num="31">
11125 There are no Java programming language or JNI stack frames at the specified depth.
11126 </errorid>
11127 <errorid id="JVMTI_ERROR_OPAQUE_FRAME" num="32">
11128 Information about the frame is not available (e.g. for native frames).
11129 </errorid>
11130 <errorid id="JVMTI_ERROR_DUPLICATE" num="40">
11131 Item already set.
11132 </errorid>
11133 <errorid id="JVMTI_ERROR_NOT_FOUND" num="41">
11134 Desired element (e.g. field or breakpoint) not found
11135 </errorid>
11136 <errorid id="JVMTI_ERROR_NOT_MONITOR_OWNER" num="51">
11137 This thread doesn't own the raw monitor.
11138 </errorid>
11139 <errorid id="JVMTI_ERROR_INTERRUPT" num="52">
11140 The call has been interrupted before completion.
11141 </errorid>
11142 <errorid id="JVMTI_ERROR_UNMODIFIABLE_CLASS" num="79">
11143 The class cannot be modified.
11144 </errorid>
11145 <errorid id="JVMTI_ERROR_NOT_AVAILABLE" num="98">
11146 The functionality is not available in this virtual machine.
11147 </errorid>
11148 <errorid id="JVMTI_ERROR_ABSENT_INFORMATION" num="101">
11149 The requested information is not available.
11150 </errorid>
11151 <errorid id="JVMTI_ERROR_INVALID_EVENT_TYPE" num="102">
11152 The specified event type ID is not recognized.
11153 </errorid>
11154 <errorid id="JVMTI_ERROR_NATIVE_METHOD" num="104">
11155 The requested information is not available for native method.
11156 </errorid>
11157 <errorid id="JVMTI_ERROR_CLASS_LOADER_UNSUPPORTED" num="106">
11158 The class loader does not support this operation.
11159 </errorid>
11160 </errorcategory>
11162 <errorcategory id="function-specific-errors" label="Function Specific Agent Errors">
11163 <intro>
11164 The following errors are returned by some <jvmti/> functions.
11165 They are returned in the event of invalid parameters passed by the
11166 agent or usage in an invalid context.
11167 An implementation is not required to detect these errors.
11168 </intro>
11170 <errorid id="JVMTI_ERROR_INVALID_THREAD" num="10">
11171 The passed thread is not a valid thread.
11172 </errorid>
11173 <errorid id="JVMTI_ERROR_INVALID_FIELDID" num="25">
11174 Invalid field.
11175 </errorid>
11176 <errorid id="JVMTI_ERROR_INVALID_METHODID" num="23">
11177 Invalid method.
11178 </errorid>
11179 <errorid id="JVMTI_ERROR_INVALID_LOCATION" num="24">
11180 Invalid location.
11181 </errorid>
11182 <errorid id="JVMTI_ERROR_INVALID_OBJECT" num="20">
11183 Invalid object.
11184 </errorid>
11185 <errorid id="JVMTI_ERROR_INVALID_CLASS" num="21">
11186 Invalid class.
11187 </errorid>
11188 <errorid id="JVMTI_ERROR_TYPE_MISMATCH" num="34">
11189 The variable is not an appropriate type for the function used.
11190 </errorid>
11191 <errorid id="JVMTI_ERROR_INVALID_SLOT" num="35">
11192 Invalid slot.
11193 </errorid>
11194 <errorid id="JVMTI_ERROR_MUST_POSSESS_CAPABILITY" num="99">
11195 The capability being used is false in this environment.
11196 </errorid>
11197 <errorid id="JVMTI_ERROR_INVALID_THREAD_GROUP" num="11">
11198 Thread group invalid.
11199 </errorid>
11200 <errorid id="JVMTI_ERROR_INVALID_MONITOR" num="50">
11201 Invalid raw monitor.
11202 </errorid>
11203 <errorid id="JVMTI_ERROR_ILLEGAL_ARGUMENT" num="103">
11204 Illegal argument.
11205 </errorid>
11206 <errorid id="JVMTI_ERROR_INVALID_TYPESTATE" num="65">
11207 The state of the thread has been modified, and is now inconsistent.
11208 </errorid>
11209 <errorid id="JVMTI_ERROR_UNSUPPORTED_VERSION" num="68">
11210 A new class file has a version number not supported by this VM.
11211 </errorid>
11212 <errorid id="JVMTI_ERROR_INVALID_CLASS_FORMAT" num="60">
11213 A new class file is malformed (the VM would return a <code>ClassFormatError</code>).
11214 </errorid>
11215 <errorid id="JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION" num="61">
11216 The new class file definitions would lead to a circular
11217 definition (the VM would return a <code>ClassCircularityError</code>).
11218 </errorid>
11219 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED" num="63">
11220 A new class file would require adding a method.
11221 </errorid>
11222 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED" num="64">
11223 A new class version changes a field.
11224 </errorid>
11225 <errorid id="JVMTI_ERROR_FAILS_VERIFICATION" num="62">
11226 The class bytes fail verification.
11227 </errorid>
11228 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED" num="66">
11229 A direct superclass is different for the new class
11230 version, or the set of directly implemented
11231 interfaces is different.
11232 </errorid>
11233 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED" num="67">
11234 A new class version does not declare a method
11235 declared in the old class version.
11236 </errorid>
11237 <errorid id="JVMTI_ERROR_NAMES_DONT_MATCH" num="69">
11238 The class name defined in the new class file is
11239 different from the name in the old class object.
11240 </errorid>
11241 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED" num="70">
11242 A new class version has different modifiers.
11243 </errorid>
11244 <errorid id="JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED" num="71">
11245 A method in the new class version has different modifiers
11246 than its counterpart in the old class version.
11247 </errorid>
11248 </errorcategory>
11249 </errorsection>
11251 <eventsection label="Events">
11252 <intro label="Handling Events" id="eventIntro">
11253 Agents can be informed of many events that occur in application
11254 programs.
11255 <p/>
11256 To handle events, designate a set of callback functions with
11257 <functionlink id="SetEventCallbacks"></functionlink>.
11258 For each event the corresponding callback function will be
11259 called.
11260 Arguments to the callback function provide additional
11261 information about the event.
11262 <p/>
11263 The callback function is usually called from within an application
11264 thread. The <jvmti/> implementation does not
11265 queue events in any way. This means
11266 that event callback functions must be written
11267 carefully. Here are some general guidelines. See
11268 the individual event descriptions for further
11269 suggestions.
11270 <p/>
11271 <ul>
11272 <li>Any exception thrown during the execution of an event callback can
11273 overwrite any current pending exception in the current application thread.
11274 Care must be taken to preserve a pending exception
11275 when an event callback makes a JNI call that might generate an exception.
11276 </li>
11277 <li>Event callback functions must be re-entrant. The <jvmti/> implementation does
11278 not queue events. If an agent needs to process events one at a time, it
11279 can use a raw monitor inside the
11280 event callback functions to serialize event processing.
11281 </li>
11282 <li>Event callback functions that execute JNI's FindClass function to load
11283 classes need to note that FindClass locates the class loader associated
11284 with the current native method. For the purposes of class loading, an
11285 event callback that includes a JNI environment as a parameter to the
11286 callback will treated as if it is a native call, where the native method
11287 is in the class of the event thread's current frame.
11288 </li>
11289 </ul>
11290 <p/>
11291 Some <jvmti/> events identify objects with JNI references.
11292 All references
11293 in <jvmti/> events are JNI local references and will become invalid
11294 after the event callback returns.
11295 Unless stated otherwise, memory referenced by pointers sent in event
11296 callbacks may not be referenced after the event callback returns.
11297 <p/>
11298 Except where stated otherwise, events are delivered on the thread
11299 that caused the event.
11300 Events are sent at the time they occur.
11301 The specification for each event includes the set of
11302 <functionlink id="GetPhase">phases</functionlink> in which it can be sent;
11303 if an event triggering activity occurs during another phase, no event
11304 is sent.
11305 <p/>
11306 A thread that generates an event does not change its execution status
11307 (for example, the event does not cause the thread to be suspended).
11308 If an agent wishes the event to result in suspension, then the agent
11309 is responsible for explicitly suspending the thread with
11310 <functionlink id="SuspendThread"></functionlink>.
11311 <p/>
11312 If an event is enabled in multiple environments, the event will be sent
11313 to each agent in the order that the environments were created.
11314 </intro>
11316 <intro label="Enabling Events" id="enablingevents">
11317 All events are initially disabled. In order to receive any
11318 event:
11319 <ul>
11320 <li>
11321 If the event requires a capability, that capability must
11322 be added with
11323 <functionlink id="AddCapabilities"></functionlink>.
11324 </li>
11325 <li>
11326 A callback for the event must be set with
11327 <functionlink id="SetEventCallbacks"></functionlink>.
11328 </li>
11329 <li>
11330 The event must be enabled with
11331 <functionlink id="SetEventNotificationMode"></functionlink>.
11332 </li>
11333 </ul>
11334 </intro>
11336 <intro label="Multiple Co-located Events" id="eventorder">
11337 In many situations it is possible for multiple events to occur
11338 at the same location in one thread. When this happens, all the events
11339 are reported through the event callbacks in the order specified in this section.
11340 <p/>
11341 If the current location is at the entry point of a method, the
11342 <eventlink id="MethodEntry"></eventlink> event is reported before
11343 any other event at the current location in the same thread.
11344 <p/>
11345 If an exception catch has been detected at the current location,
11346 either because it is the beginning of a catch clause or a native method
11347 that cleared a pending exception has returned, the
11348 <code>exceptionCatch</code> event is reported before
11349 any other event at the current location in the same thread.
11350 <p/>
11351 If a <code>singleStep</code> event or
11352 <code>breakpoint</code> event is triggered at the
11353 current location, the event is defined to occur
11354 immediately before the code at the current location is executed.
11355 These events are reported before any events which are triggered
11356 by the execution of code at the current location in the same
11357 thread (specifically:
11358 <code>exception</code>,
11359 <code>fieldAccess</code>, and
11360 <code>fieldModification</code>).
11361 If both a step and breakpoint event are triggered for the same thread and
11362 location, the step event is reported before the breakpoint event.
11363 <p/>
11364 If the current location is the exit point of a method (that is, the last
11365 location before returning to the caller), the
11366 <eventlink id="MethodExit"></eventlink> event and
11367 the <eventlink id="FramePop"></eventlink> event (if requested)
11368 are reported after all other events at the current location in the same
11369 thread. There is no specified ordering of these two events
11370 with respect to each other.
11371 <p/>
11372 Co-located events can be triggered during the processing of some other
11373 event by the agent at the same location in the same thread.
11374 If such an event, of type <i>y</i>, is triggered during the processing of
11375 an event of type <i>x</i>, and if <i>x</i>
11376 precedes <i>y</i> in the ordering specified above, the co-located event
11377 <i>y</i> is reported for the current thread and location. If <i>x</i> does not precede
11378 <i>y</i>, <i>y</i> is not reported for the current thread and location.
11379 For example, if a breakpoint is set at the current location
11380 during the processing of <eventlink id="SingleStep"></eventlink>,
11381 that breakpoint will be reported before the thread moves off the current
11382 location.
11383 <p/>The following events are never considered to be co-located with
11384 other events.
11385 <ul>
11386 <li><eventlink id="VMStart"></eventlink></li>
11387 <li><eventlink id="VMInit"></eventlink></li>
11388 <li><eventlink id="VMDeath"></eventlink></li>
11389 <li><eventlink id="ThreadStart"></eventlink></li>
11390 <li><eventlink id="ThreadEnd"></eventlink></li>
11391 <li><eventlink id="ClassLoad"></eventlink></li>
11392 <li><eventlink id="ClassPrepare"></eventlink></li>
11393 </ul>
11394 </intro>
11396 <intro label="Event Callbacks" id="jvmtiEventCallbacks">
11397 The event callback structure below is used to specify the handler function
11398 for events. It is set with the
11399 <functionlink id="SetEventCallbacks"></functionlink> function.
11400 </intro>
11402 <event label="Single Step"
11403 id="SingleStep" const="JVMTI_EVENT_SINGLE_STEP" filtered="thread" num="60">
11404 <description>
11405 Single step events allow the agent to trace thread execution
11406 at the finest granularity allowed by the VM. A single step event is
11407 generated whenever a thread reaches a new location.
11408 Typically, single step events represent the completion of one VM
11409 instruction as defined in <vmspec/>. However, some implementations
11410 may define locations differently. In any case the
11411 <code>method</code> and <code>location</code>
11412 parameters uniquely identify the current location and allow
11413 the mapping to source file and line number when that information is
11414 available.
11415 <p/>
11416 No single step events are generated from within native methods.
11417 </description>
11418 <origin>jvmdi</origin>
11419 <capabilities>
11420 <required id="can_generate_single_step_events"></required>
11421 </capabilities>
11422 <parameters>
11423 <param id="jni_env">
11424 <outptr>
11425 <struct>JNIEnv</struct>
11426 </outptr>
11427 <description>
11428 The JNI environment of the event (current) thread
11429 </description>
11430 </param>
11431 <param id="thread">
11432 <jthread/>
11433 <description>
11434 Thread about to execution a new instruction
11435 </description>
11436 </param>
11437 <param id="klass">
11438 <jclass method="method"/>
11439 <description>
11440 Class of the method about to execute a new instruction
11441 </description>
11442 </param>
11443 <param id="method">
11444 <jmethodID class="klass"/>
11445 <description>
11446 Method about to execute a new instruction
11447 </description>
11448 </param>
11449 <param id="location">
11450 <jlocation/>
11451 <description>
11452 Location of the new instruction
11453 </description>
11454 </param>
11455 </parameters>
11456 </event>
11458 <event label="Breakpoint"
11459 id="Breakpoint" const="JVMTI_EVENT_BREAKPOINT" filtered="thread" num="62">
11460 <description>
11461 Breakpoint events are generated whenever a thread reaches a location
11462 designated as a breakpoint with <functionlink id="SetBreakpoint"></functionlink>.
11463 The <code>method</code> and <code>location</code>
11464 parameters uniquely identify the current location and allow
11465 the mapping to source file and line number when that information is
11466 available.
11467 </description>
11468 <origin>jvmdi</origin>
11469 <capabilities>
11470 <required id="can_generate_breakpoint_events"></required>
11471 </capabilities>
11472 <parameters>
11473 <param id="jni_env">
11474 <outptr>
11475 <struct>JNIEnv</struct>
11476 </outptr>
11477 <description>
11478 The JNI environment of the event (current) thread.
11479 </description>
11480 </param>
11481 <param id="thread">
11482 <jthread/>
11483 <description>
11484 Thread that hit the breakpoint
11485 </description>
11486 </param>
11487 <param id="klass">
11488 <jclass method="method"/>
11489 <description>
11490 Class of the method that hit the breakpoint
11491 </description>
11492 </param>
11493 <param id="method">
11494 <jmethodID class="klass"/>
11495 <description>
11496 Method that hit the breakpoint
11497 </description>
11498 </param>
11499 <param id="location">
11500 <jlocation/>
11501 <description>
11502 location of the breakpoint
11503 </description>
11504 </param>
11505 </parameters>
11506 </event>
11508 <event label="Field Access"
11509 id="FieldAccess" const="JVMTI_EVENT_FIELD_ACCESS" filtered="thread" num="63">
11510 <description>
11511 Field access events are generated whenever a thread accesses
11512 a field that was designated as a watchpoint
11513 with <functionlink id="SetFieldAccessWatch"></functionlink>.
11514 The <code>method</code> and <code>location</code>
11515 parameters uniquely identify the current location and allow
11516 the mapping to source file and line number when that information is
11517 available.
11518 </description>
11519 <origin>jvmdi</origin>
11520 <capabilities>
11521 <required id="can_generate_field_access_events"></required>
11522 </capabilities>
11523 <parameters>
11524 <param id="jni_env">
11525 <outptr>
11526 <struct>JNIEnv</struct>
11527 </outptr>
11528 <description>
11529 The JNI environment of the event (current) thread
11530 </description>
11531 </param>
11532 <param id="thread">
11533 <jthread/>
11534 <description>
11535 Thread accessing the field
11536 </description>
11537 </param>
11538 <param id="klass">
11539 <jclass method="method"/>
11540 <description>
11541 Class of the method where the access is occurring
11542 </description>
11543 </param>
11544 <param id="method">
11545 <jmethodID class="klass"/>
11546 <description>
11547 Method where the access is occurring
11548 </description>
11549 </param>
11550 <param id="location">
11551 <jlocation/>
11552 <description>
11553 Location where the access is occurring
11554 </description>
11555 </param>
11556 <param id="field_klass">
11557 <jclass field="field"/>
11558 <description>
11559 Class of the field being accessed
11560 </description>
11561 </param>
11562 <param id="object">
11563 <jobject/>
11564 <description>
11565 Object with the field being accessed if the field is an
11566 instance field; <code>NULL</code> otherwise
11567 </description>
11568 </param>
11569 <param id="field">
11570 <jfieldID class="field_klass"/>
11571 <description>
11572 Field being accessed
11573 </description>
11574 </param>
11575 </parameters>
11576 </event>
11578 <event label="Field Modification"
11579 id="FieldModification" const="JVMTI_EVENT_FIELD_MODIFICATION" filtered="thread" num="64">
11580 <description>
11581 Field modification events are generated whenever a thread modifies
11582 a field that was designated as a watchpoint
11583 with <functionlink id="SetFieldModificationWatch"></functionlink>.
11584 The <code>method</code> and <code>location</code>
11585 parameters uniquely identify the current location and allow
11586 the mapping to source file and line number when that information is
11587 available.
11588 </description>
11589 <origin>jvmdi</origin>
11590 <capabilities>
11591 <required id="can_generate_field_modification_events"></required>
11592 </capabilities>
11593 <parameters>
11594 <param id="jni_env">
11595 <outptr>
11596 <struct>JNIEnv</struct>
11597 </outptr>
11598 <description>
11599 The JNI environment of the event (current) thread
11600 </description>
11601 </param>
11602 <param id="thread">
11603 <jthread/>
11604 <description>
11605 Thread modifying the field
11606 </description>
11607 </param>
11608 <param id="klass">
11609 <jclass method="method"/>
11610 <description>
11611 Class of the method where the modification is occurring
11612 </description>
11613 </param>
11614 <param id="method">
11615 <jmethodID class="klass"/>
11616 <description>
11617 Method where the modification is occurring
11618 </description>
11619 </param>
11620 <param id="location">
11621 <jlocation/>
11622 <description>
11623 Location where the modification is occurring
11624 </description>
11625 </param>
11626 <param id="field_klass">
11627 <jclass field="field"/>
11628 <description>
11629 Class of the field being modified
11630 </description>
11631 </param>
11632 <param id="object">
11633 <jobject/>
11634 <description>
11635 Object with the field being modified if the field is an
11636 instance field; <code>NULL</code> otherwise
11637 </description>
11638 </param>
11639 <param id="field">
11640 <jfieldID class="field_klass"/>
11641 <description>
11642 Field being modified
11643 </description>
11644 </param>
11645 <param id="signature_type">
11646 <char/>
11647 <description>
11648 Signature type of the new value
11649 </description>
11650 </param>
11651 <param id="new_value">
11652 <jvalue/>
11653 <description>
11654 The new value
11655 </description>
11656 </param>
11657 </parameters>
11658 </event>
11660 <event label="Frame Pop"
11661 id="FramePop" const="JVMTI_EVENT_FRAME_POP" filtered="thread" num="61">
11662 <description>
11663 Frame pop events are generated upon exit from a single method
11664 in a single frame as specified
11665 in a call to <functionlink id="NotifyFramePop"></functionlink>.
11666 This is true whether termination is caused by
11667 executing its return instruction
11668 or by throwing an exception to its caller
11669 (see <paramlink id="was_popped_by_exception"></paramlink>).
11670 However, frame pops caused by the <functionlink id="PopFrame"/>
11671 function are not reported.
11672 <p/>
11673 The location reported by <functionlink id="GetFrameLocation"></functionlink>
11674 identifies the executable location in the returning method,
11675 immediately prior to the return.
11676 </description>
11677 <origin>jvmdi</origin>
11678 <capabilities>
11679 <required id="can_generate_frame_pop_events"></required>
11680 </capabilities>
11681 <parameters>
11682 <param id="jni_env">
11683 <outptr>
11684 <struct>JNIEnv</struct>
11685 </outptr>
11686 <description>
11687 The JNI environment of the event (current) thread
11688 </description>
11689 </param>
11690 <param id="thread">
11691 <jthread/>
11692 <description>
11693 Thread that is popping the frame
11694 </description>
11695 </param>
11696 <param id="klass">
11697 <jclass method="method"/>
11698 <description>
11699 Class of the method being popped
11700 </description>
11701 </param>
11702 <param id="method">
11703 <jmethodID class="klass"/>
11704 <description>
11705 Method being popped
11706 </description>
11707 </param>
11708 <param id="was_popped_by_exception">
11709 <jboolean/>
11710 <description>
11711 True if frame was popped by a thrown exception.
11712 False if method exited through its return instruction.
11713 </description>
11714 </param>
11715 </parameters>
11716 </event>
11718 <event label="Method Entry"
11719 id="MethodEntry" const="JVMTI_EVENT_METHOD_ENTRY" filtered="thread" num="65">
11720 <description>
11721 Method entry events are generated upon entry of Java
11722 programming language methods (including native methods).
11723 <p/>
11724 The location reported by <functionlink id="GetFrameLocation"></functionlink>
11725 identifies the initial executable location in
11726 the method.
11727 <p/>
11728 Enabling method
11729 entry or exit events will significantly degrade performance on many platforms and is thus
11730 not advised for performance critical usage (such as profiling).
11731 <internallink id="bci">Bytecode instrumentation</internallink> should be
11732 used in these cases.
11733 </description>
11734 <origin>jvmdi</origin>
11735 <capabilities>
11736 <required id="can_generate_method_entry_events"></required>
11737 </capabilities>
11738 <parameters>
11739 <param id="jni_env">
11740 <outptr>
11741 <struct>JNIEnv</struct>
11742 </outptr>
11743 <description>
11744 The JNI environment of the event (current) thread
11745 </description>
11746 </param>
11747 <param id="thread">
11748 <jthread/>
11749 <description>
11750 Thread entering the method
11751 </description>
11752 </param>
11753 <param id="klass">
11754 <jclass method="method"/>
11755 <description>
11756 Class of the method being entered
11757 </description>
11758 </param>
11759 <param id="method">
11760 <jmethodID class="klass"/>
11761 <description>
11762 Method being entered
11763 </description>
11764 </param>
11765 </parameters>
11766 </event>
11768 <event label="Method Exit"
11769 id="MethodExit" const="JVMTI_EVENT_METHOD_EXIT" filtered="thread" num="66">
11770 <description>
11771 Method exit events are generated upon exit from Java
11772 programming language methods (including native methods).
11773 This is true whether termination is caused by
11774 executing its return instruction
11775 or by throwing an exception to its caller
11776 (see <paramlink id="was_popped_by_exception"></paramlink>).
11777 <p/>
11778 The <code>method</code> field uniquely identifies the
11779 method being entered or exited. The <code>frame</code> field provides
11780 access to the stack frame for the method.
11781 <p/>
11782 The location reported by <functionlink id="GetFrameLocation"></functionlink>
11783 identifies the executable location in the returning method
11784 immediately prior to the return.
11785 <p/>
11786 Enabling method
11787 entry or exit events will significantly degrade performance on many platforms and is thus
11788 not advised for performance critical usage (such as profiling).
11789 <internallink id="bci">Bytecode instrumentation</internallink> should be
11790 used in these cases.
11791 </description>
11792 <origin>jvmdi</origin>
11793 <capabilities>
11794 <required id="can_generate_method_exit_events"></required>
11795 </capabilities>
11796 <parameters>
11797 <param id="jni_env">
11798 <outptr>
11799 <struct>JNIEnv</struct>
11800 </outptr>
11801 <description>
11802 The JNI environment of the event (current) thread
11803 </description>
11804 </param>
11805 <param id="thread">
11806 <jthread/>
11807 <description>
11808 Thread exiting the method
11809 </description>
11810 </param>
11811 <param id="klass">
11812 <jclass method="method"/>
11813 <description>
11814 Class of the method being exited
11815 </description>
11816 </param>
11817 <param id="method">
11818 <jmethodID class="klass"/>
11819 <description>
11820 Method being exited
11821 </description>
11822 </param>
11823 <param id="was_popped_by_exception">
11824 <jboolean/>
11825 <description>
11826 True if frame was popped by a thrown exception.
11827 False if method exited through its return instruction.
11828 </description>
11829 </param>
11830 <param id="return_value">
11831 <jvalue/>
11832 <description>
11833 The return value of the method being exited.
11834 Undefined and should not be used if
11835 <paramlink id="was_popped_by_exception"></paramlink>
11836 is true.
11837 </description>
11838 </param>
11839 </parameters>
11840 </event>
11842 <event label="Native Method Bind" phase="any"
11843 id="NativeMethodBind" const="JVMTI_EVENT_NATIVE_METHOD_BIND" num="67">
11844 <description>
11845 A Native Method Bind event is sent when a VM binds a
11846 Java programming language native method
11847 to the address of a function that implements the native method.
11848 This will occur when the native method is called for the first time
11849 and also occurs when the JNI function <code>RegisterNatives</code> is called.
11850 This event allows the bind to be redirected to an agent-specified
11851 proxy function.
11852 This event is not sent when the native method is unbound.
11853 Typically, this proxy function will need to be specific to a
11854 particular method or, to handle the general case, automatically
11855 generated assembly code, since after instrumentation code is
11856 executed the function at the original binding
11857 address will usually be invoked.
11858 The original binding can be restored or the redirection changed
11859 by use of the JNI function <code>RegisterNatives</code>.
11860 Some events may be sent during the primordial phase, JNI and
11861 most of <jvmti/> cannot be used at this time but the method and
11862 address can be saved for use later.
11863 </description>
11864 <origin>new</origin>
11865 <capabilities>
11866 <required id="can_generate_native_method_bind_events"></required>
11867 </capabilities>
11868 <parameters>
11869 <param id="jni_env">
11870 <outptr>
11871 <struct>JNIEnv</struct>
11872 </outptr>
11873 <description>
11874 The JNI environment of the event (current) thread
11875 Will be <code>NULL</code> if sent during the primordial
11876 <functionlink id="GetPhase">phase</functionlink>.
11877 </description>
11878 </param>
11879 <param id="thread">
11880 <jthread/>
11881 <description>
11882 Thread requesting the bind
11883 </description>
11884 </param>
11885 <param id="klass">
11886 <jclass method="method"/>
11887 <description>
11888 Class of the method being bound
11889 </description>
11890 </param>
11891 <param id="method">
11892 <jmethodID class="klass"/>
11893 <description>
11894 Native method being bound
11895 </description>
11896 </param>
11897 <param id="address">
11898 <outptr><void/></outptr>
11899 <description>
11900 The address the VM is about to bind to--that is, the
11901 address of the implementation of the native method
11902 </description>
11903 </param>
11904 <param id="new_address_ptr">
11905 <agentbuf><void/></agentbuf>
11906 <description>
11907 if the referenced address is changed (that is, if
11908 <code>*new_address_ptr</code> is set), the binding
11909 will instead be made to the supplied address.
11910 </description>
11911 </param>
11912 </parameters>
11913 </event>
11915 <event label="Exception"
11916 id="Exception" const="JVMTI_EVENT_EXCEPTION" filtered="thread" num="58">
11917 <description>
11918 Exception events are generated whenever an exception is first detected
11919 in a Java programming language method.
11920 Where "exception" means any <code>java.lang.Throwable</code>.
11921 The exception may have been thrown by a Java programming language or native
11922 method, but in the case of native methods, the event is not generated
11923 until the exception is first seen by a Java programming language method. If an exception is
11924 set and cleared in a native method (and thus is never visible to Java programming language code),
11925 no exception event is generated.
11926 <p/>
11927 The <code>method</code> and <code>location</code>
11928 parameters uniquely identify the current location
11929 (where the exception was detected) and allow
11930 the mapping to source file and line number when that information is
11931 available. The <code>exception</code> field identifies the thrown
11932 exception object. The <code>catch_method</code>
11933 and <code>catch_location</code> identify the location of the catch clause,
11934 if any, that handles the thrown exception. If there is no such catch clause,
11935 each field is set to 0. There is no guarantee that the thread will ever
11936 reach this catch clause. If there are native methods on the call stack
11937 between the throw location and the catch clause, the exception may
11938 be reset by one of those native methods.
11939 Similarly, exceptions that are reported as uncaught (<code>catch_klass</code>
11940 et al. set to 0) may in fact be caught by native code.
11941 Agents can check for these occurrences by monitoring
11942 <eventlink id="ExceptionCatch"></eventlink> events.
11943 Note that finally clauses are implemented as catch and re-throw. Therefore they
11944 will be reported in the catch location.
11945 </description>
11946 <origin>jvmdi</origin>
11947 <capabilities>
11948 <required id="can_generate_exception_events"></required>
11949 </capabilities>
11950 <parameters>
11951 <param id="jni_env">
11952 <outptr>
11953 <struct>JNIEnv</struct>
11954 </outptr>
11955 <description>
11956 The JNI environment of the event (current) thread
11957 </description>
11958 </param>
11959 <param id="thread">
11960 <jthread/>
11961 <description>
11962 Thread generating the exception
11963 </description>
11964 </param>
11965 <param id="klass">
11966 <jclass method="method"/>
11967 <description>
11968 Class generating the exception
11969 </description>
11970 </param>
11971 <param id="method">
11972 <jmethodID class="klass"/>
11973 <description>
11974 Method generating the exception
11975 </description>
11976 </param>
11977 <param id="location">
11978 <jlocation/>
11979 <description>
11980 Location where exception occurred
11981 </description>
11982 </param>
11983 <param id="exception">
11984 <jobject/>
11985 <description>
11986 The exception being thrown
11987 </description>
11988 </param>
11989 <param id="catch_klass">
11990 <jclass method="catch_method"/>
11991 <description>
11992 Class that will catch the exception, or <code>NULL</code> if no known catch
11993 </description>
11994 </param>
11995 <param id="catch_method">
11996 <jmethodID class="catch_klass"/>
11997 <description>
11998 Method that will catch the exception, or <code>NULL</code> if no known catch
11999 </description>
12000 </param>
12001 <param id="catch_location">
12002 <jlocation/>
12003 <description>
12004 location which will catch the exception or zero if no known catch
12005 </description>
12006 </param>
12007 </parameters>
12008 </event>
12010 <event label="Exception Catch"
12011 id="ExceptionCatch" const="JVMTI_EVENT_EXCEPTION_CATCH" filtered="thread" num="59">
12012 <description>
12013 Exception catch events are generated whenever a thrown exception is caught.
12014 Where "exception" means any <code>java.lang.Throwable</code>.
12015 If the exception is caught in a Java programming language method, the event is generated
12016 when the catch clause is reached. If the exception is caught in a native
12017 method, the event is generated as soon as control is returned to a Java programming language
12018 method. Exception catch events are generated for any exception for which
12019 a throw was detected in a Java programming language method.
12020 Note that finally clauses are implemented as catch and re-throw. Therefore they
12021 will generate exception catch events.
12022 <p/>
12023 The <code>method</code> and <code>location</code>
12024 parameters uniquely identify the current location
12025 and allow the mapping to source file and line number when that information is
12026 available. For exceptions caught in a Java programming language method, the
12027 <code>exception</code> object identifies the exception object. Exceptions
12028 caught in native methods are not necessarily available by the time the
12029 exception catch is reported, so the <code>exception</code> field is set
12030 to <code>NULL</code>.
12031 </description>
12032 <origin>jvmdi</origin>
12033 <capabilities>
12034 <required id="can_generate_exception_events"></required>
12035 </capabilities>
12036 <parameters>
12037 <param id="jni_env">
12038 <outptr>
12039 <struct>JNIEnv</struct>
12040 </outptr>
12041 <description>
12042 The JNI environment of the event (current) thread
12043 </description>
12044 </param>
12045 <param id="thread">
12046 <jthread/>
12047 <description>
12048 Thread catching the exception
12049 </description>
12050 </param>
12051 <param id="klass">
12052 <jclass method="method"/>
12053 <description>
12054 Class catching the exception
12055 </description>
12056 </param>
12057 <param id="method">
12058 <jmethodID class="klass"/>
12059 <description>
12060 Method catching the exception
12061 </description>
12062 </param>
12063 <param id="location">
12064 <jlocation/>
12065 <description>
12066 Location where exception is being caught
12067 </description>
12068 </param>
12069 <param id="exception">
12070 <jobject/>
12071 <description>
12072 Exception being caught
12073 </description>
12074 </param>
12075 </parameters>
12076 </event>
12078 <event label="Thread Start"
12079 id="ThreadStart" const="JVMTI_EVENT_THREAD_START" num="52" phase="start">
12080 <description>
12081 Thread start events are generated by a new thread before its initial
12082 method executes.
12083 <p/>
12084 A thread may be listed in the array returned by
12085 <functionlink id="GetAllThreads"></functionlink>
12086 before its thread start event is generated.
12087 It is possible for other events to be generated
12088 on a thread before its thread start event.
12089 <p/>
12090 The event is sent on the newly started <paramlink id="thread"></paramlink>.
12091 </description>
12092 <origin>jvmdi</origin>
12093 <capabilities>
12094 </capabilities>
12095 <parameters>
12096 <param id="jni_env">
12097 <outptr>
12098 <struct>JNIEnv</struct>
12099 </outptr>
12100 <description>
12101 The JNI environment of the event (current) thread.
12102 </description>
12103 </param>
12104 <param id="thread">
12105 <jthread/>
12106 <description>
12107 Thread starting
12108 </description>
12109 </param>
12110 </parameters>
12111 </event>
12113 <event label="Thread End"
12114 id="ThreadEnd" const="JVMTI_EVENT_THREAD_END" filtered="thread" num="53" phase="start">
12115 <description>
12116 Thread end events are generated by a terminating thread
12117 after its initial method has finished execution.
12118 <p/>
12119 A thread may be listed in the array returned by
12120 <functionlink id="GetAllThreads"></functionlink>
12121 after its thread end event is generated.
12122 No events are generated on a thread
12123 after its thread end event.
12124 <p/>
12125 The event is sent on the dying <paramlink id="thread"></paramlink>.
12126 </description>
12127 <origin>jvmdi</origin>
12128 <capabilities>
12129 </capabilities>
12130 <parameters>
12131 <param id="jni_env">
12132 <outptr>
12133 <struct>JNIEnv</struct>
12134 </outptr>
12135 <description>
12136 The JNI environment of the event (current) thread.
12137 </description>
12138 </param>
12139 <param id="thread">
12140 <jthread/>
12141 <description>
12142 Thread ending
12143 </description>
12144 </param>
12145 </parameters>
12146 </event>
12148 <event label="Class Load"
12149 id="ClassLoad" const="JVMTI_EVENT_CLASS_LOAD" filtered="thread" phase="start" num="55">
12150 <description>
12151 A class load event is generated when a class is first loaded. The order
12152 of class load events generated by a particular thread are guaranteed
12153 to match the order of class loading within that thread.
12154 Array class creation does not generate a class load event.
12155 The creation of a primitive class (for example, java.lang.Integer.TYPE)
12156 does not generate a class load event.
12157 <p/>
12158 This event is sent at an early stage in loading the class. As
12159 a result the class should be used carefully. Note, for example,
12160 that methods and fields are not yet loaded, so queries for methods,
12161 fields, subclasses, and so on will not give correct results.
12162 See "Loading of Classes and Interfaces" in the <i>Java Language
12163 Specification</i>. For most
12164 purposes the <eventlink id="ClassPrepare"></eventlink> event will
12165 be more useful.
12166 </description>
12167 <origin>jvmdi</origin>
12168 <capabilities>
12169 </capabilities>
12170 <parameters>
12171 <param id="jni_env">
12172 <outptr>
12173 <struct>JNIEnv</struct>
12174 </outptr>
12175 <description>
12176 The JNI environment of the event (current) thread
12177 </description>
12178 </param>
12179 <param id="thread">
12180 <jthread/>
12181 <description>
12182 Thread loading the class
12183 </description>
12184 </param>
12185 <param id="klass">
12186 <jclass/>
12187 <description>
12188 Class being loaded
12189 </description>
12190 </param>
12191 </parameters>
12192 </event>
12194 <elide>
12195 <event label="Class Unload"
12196 id="ClassUnload" const="JVMTI_EVENT_CLASS_UNLOAD" num="57">
12197 <description>
12198 A class unload event is generated when the class is about to be unloaded.
12199 Class unload events take place during garbage collection and must be
12200 handled extremely carefully. The garbage collector holds many locks
12201 and has suspended all other threads, so the event handler cannot depend
12202 on the ability to acquire any locks. The class unload event handler should
12203 do as little as possible, perhaps by queuing information to be processed
12204 later. In particular, the <code>jclass</code> should be used only in
12205 the JNI function <code>isSameObject</code> or in the following <jvmti/> functions:
12206 <ul>
12207 <li><functionlink id="GetClassSignature"></functionlink></li>
12208 <li><functionlink id="GetSourceFileName"></functionlink></li>
12209 <li><functionlink id="IsInterface"></functionlink></li>
12210 <li><functionlink id="IsArrayClass"></functionlink></li>
12211 </ul>
12212 </description>
12213 <origin>jvmdi</origin>
12214 <capabilities>
12215 </capabilities>
12216 <parameters>
12217 <param id="jni_env">
12218 <outptr>
12219 <struct>JNIEnv</struct>
12220 </outptr>
12221 <description>
12222 The JNI environment of the event (current) thread
12223 </description>
12224 </param>
12225 <param id="thread">
12226 <jthread/>
12227 <description>
12228 Thread generating the class unload
12229 </description>
12230 </param>
12231 <param id="klass">
12232 <jclass/>
12233 <description>
12234 Class being unloaded
12235 </description>
12236 </param>
12237 </parameters>
12238 </event>
12239 </elide>
12241 <event label="Class Prepare"
12242 id="ClassPrepare" const="JVMTI_EVENT_CLASS_PREPARE" filtered="thread" phase="start" num="56">
12243 <description>
12244 A class prepare event is generated when class preparation is complete.
12245 At this point, class fields, methods, and implemented interfaces are
12246 available, and no code from the class has been executed. Since array
12247 classes never have fields or methods, class prepare events are not
12248 generated for them. Class prepare events are not generated for
12249 primitive classes (for example, <code>java.lang.Integer.TYPE</code>).
12250 </description>
12251 <origin>jvmdi</origin>
12252 <capabilities>
12253 </capabilities>
12254 <parameters>
12255 <param id="jni_env">
12256 <outptr>
12257 <struct>JNIEnv</struct>
12258 </outptr>
12259 <description>
12260 The JNI environment of the event (current) thread
12261 </description>
12262 </param>
12263 <param id="thread">
12264 <jthread/>
12265 <description>
12266 Thread generating the class prepare
12267 </description>
12268 </param>
12269 <param id="klass">
12270 <jclass/>
12271 <description>
12272 Class being prepared
12273 </description>
12274 </param>
12275 </parameters>
12276 </event>
12278 <event label="Class File Load Hook" phase="any"
12279 id="ClassFileLoadHook" const="JVMTI_EVENT_CLASS_FILE_LOAD_HOOK" num="54">
12280 <description>
12281 This event is sent when the VM obtains class file data,
12282 but before it constructs
12283 the in-memory representation for that class.
12284 This event is also sent when the class is being modified by the
12285 <functionlink id="RetransformClasses"/> function or
12286 the <functionlink id="RedefineClasses"/> function,
12287 called in any <jvmti/> environment.
12288 The agent can instrument
12289 the existing class file data sent by the VM to include profiling/debugging hooks.
12290 See the description of
12291 <internallink id="bci">bytecode instrumentation</internallink>
12292 for usage information.
12293 <p/>
12294 This event may be sent before the VM is initialized (the primordial
12295 <functionlink id="GetPhase">phase</functionlink>). During this time
12296 no VM resources should be created. Some classes might not be compatible
12297 with the function (eg. ROMized classes) and this event will not be
12298 generated for these classes.
12299 <p/>
12300 The agent must allocate the space for the modified
12301 class file data buffer
12302 using the memory allocation function
12303 <functionlink id="Allocate"></functionlink> because the
12304 VM is responsible for freeing the new class file data buffer
12305 using <functionlink id="Deallocate"></functionlink>.
12306 Note that <functionlink id="Allocate"></functionlink>
12307 is permitted during the primordial phase.
12308 <p/>
12309 If the agent wishes to modify the class file, it must set
12310 <code>new_class_data</code> to point
12311 to the newly instrumented class file data buffer and set
12312 <code>new_class_data_len</code> to the length of that
12313 buffer before returning
12314 from this call. If no modification is desired, the agent simply
12315 does not set <code>new_class_data</code>. If multiple agents
12316 have enabled this event the results are chained. That is, if
12317 <code>new_class_data</code> has been set, it becomes the
12318 <code>class_data</code> for the next agent.
12319 <p/>
12320 The order that this event is sent to each environment differs
12321 from other events.
12322 This event is sent to environments in the following order:
12323 <ul>
12324 <li><fieldlink id="can_retransform_classes"
12325 struct="jvmtiCapabilities">retransformation
12326 incapable</fieldlink>
12327 environments, in the
12328 order in which they were created
12329 </li>
12330 <li><fieldlink id="can_retransform_classes"
12331 struct="jvmtiCapabilities">retransformation
12332 capable</fieldlink>
12333 environments, in the
12334 order in which they were created
12335 </li>
12336 </ul>
12337 When triggered by <functionlink id="RetransformClasses"/>,
12338 this event is sent only to <fieldlink id="can_retransform_classes"
12339 struct="jvmtiCapabilities">retransformation
12340 capable</fieldlink>
12341 environments.
12342 </description>
12343 <origin>jvmpi</origin>
12344 <capabilities>
12345 <capability id="can_generate_all_class_hook_events"></capability>
12346 </capabilities>
12347 <parameters>
12348 <param id="jni_env">
12349 <outptr>
12350 <struct>JNIEnv</struct>
12351 </outptr>
12352 <description>
12353 The JNI environment of the event (current) thread.
12354 Will be <code>NULL</code> if sent during the primordial
12355 <functionlink id="GetPhase">phase</functionlink>.
12356 </description>
12357 </param>
12358 <param id="class_being_redefined">
12359 <jclass/>
12360 <description>
12361 The class being
12362 <functionlink id="RedefineClasses">redefined</functionlink> or
12363 <functionlink id="RetransformClasses">retransformed</functionlink>.
12364 <code>NULL</code> if sent by class load.
12365 </description>
12366 </param>
12367 <param id="loader">
12368 <jobject/>
12369 <description>
12370 The class loader loading the class.
12371 <code>NULL</code> if the bootstrap class loader.
12372 </description>
12373 </param>
12374 <param id="name">
12375 <vmbuf><char/></vmbuf>
12376 <description>
12377 Name of class being loaded as a VM internal qualified name
12378 (for example, "java/util/List"), encoded as a
12379 <internallink id="mUTF">modified UTF-8</internallink> string.
12380 Note: if the class is defined with a <code>NULL</code> name or
12381 without a name specified, <code>name</code> will be <code>NULL</code>.
12382 </description>
12383 </param>
12384 <param id="protection_domain">
12385 <jobject/>
12386 <description>
12387 The <code>ProtectionDomain</code> of the class.
12388 </description>
12389 </param>
12390 <param id="class_data_len">
12391 <jint/>
12392 <description>
12393 Length of current class file data buffer.
12394 </description>
12395 </param>
12396 <param id="class_data">
12397 <vmbuf><uchar/></vmbuf>
12398 <description>
12399 Pointer to the current class file data buffer.
12400 </description>
12401 </param>
12402 <param id="new_class_data_len">
12403 <outptr><jint/></outptr>
12404 <description>
12405 Pointer to the length of the new class file data buffer.
12406 </description>
12407 </param>
12408 <param id="new_class_data">
12409 <agentbuf incount="new_class_data_len"><uchar/></agentbuf>
12410 <description>
12411 Pointer to the pointer to the instrumented class file data buffer.
12412 </description>
12413 </param>
12414 </parameters>
12415 </event>
12417 <event label="VM Start Event"
12418 id="VMStart" const="JVMTI_EVENT_VM_START" num="57" phase="start">
12419 <description>
12420 The VM initialization event signals the start of the VM.
12421 At this time JNI is live but the VM is not yet fully initialized.
12422 Once this event is generated, the agent is free to call any JNI function.
12423 This event signals the beginning of the start phase,
12424 <jvmti/> functions permitted in the start phase may be called.
12425 <p/>
12426 In the case of VM start-up failure, this event will not be sent.
12427 </description>
12428 <origin>jvmdi</origin>
12429 <capabilities>
12430 </capabilities>
12431 <parameters>
12432 <param id="jni_env">
12433 <outptr>
12434 <struct>JNIEnv</struct>
12435 </outptr>
12436 <description>
12437 The JNI environment of the event (current) thread.
12438 </description>
12439 </param>
12440 </parameters>
12441 </event>
12443 <event label="VM Initialization Event"
12444 id="VMInit" const="JVMTI_EVENT_VM_INIT" num="50">
12445 <description>
12446 The VM initialization event signals the completion of VM initialization. Once
12447 this event is generated, the agent is free to call any JNI or <jvmti/>
12448 function. The VM initialization event can be preceded by or can be concurrent
12449 with other events, but
12450 the preceding events should be handled carefully, if at all, because the
12451 VM has not completed its initialization. The thread start event for the
12452 main application thread is guaranteed not to occur until after the
12453 handler for the VM initialization event returns.
12454 <p/>
12455 In the case of VM start-up failure, this event will not be sent.
12456 </description>
12457 <origin>jvmdi</origin>
12458 <capabilities>
12459 </capabilities>
12460 <parameters>
12461 <param id="jni_env">
12462 <outptr>
12463 <struct>JNIEnv</struct>
12464 </outptr>
12465 <description>
12466 The JNI environment of the event (current) thread.
12467 </description>
12468 </param>
12469 <param id="thread">
12470 <jthread/>
12471 <description>
12472 The initial thread
12473 </description>
12474 </param>
12475 </parameters>
12476 </event>
12478 <event label="VM Death Event"
12479 id="VMDeath" const="JVMTI_EVENT_VM_DEATH" num="51">
12480 <description>
12481 The VM death event notifies the agent of the termination of the VM.
12482 No events will occur after the VMDeath event.
12483 <p/>
12484 In the case of VM start-up failure, this event will not be sent.
12485 Note that <internallink id="onunload">Agent_OnUnload</internallink>
12486 will still be called in these cases.
12487 </description>
12488 <origin>jvmdi</origin>
12489 <capabilities>
12490 </capabilities>
12491 <parameters>
12492 <param id="jni_env">
12493 <outptr>
12494 <struct>JNIEnv</struct>
12495 </outptr>
12496 <description>
12497 The JNI environment of the event (current) thread
12498 </description>
12499 </param>
12500 </parameters>
12501 </event>
12503 <event label="Compiled Method Load"
12504 id="CompiledMethodLoad" const="JVMTI_EVENT_COMPILED_METHOD_LOAD" num="68">
12505 <description>
12506 Sent when a method is compiled and loaded into memory by the VM.
12507 If it is unloaded, the <eventlink id="CompiledMethodUnload"/> event is sent.
12508 If it is moved, the <eventlink id="CompiledMethodUnload"/> event is sent,
12509 followed by a new <code>CompiledMethodLoad</code> event.
12510 Note that a single method may have multiple compiled forms, and that
12511 this event will be sent for each form.
12512 Note also that several methods may be inlined into a single
12513 address range, and that this event will be sent for each method.
12514 <p/>
12515 These events can be sent after their initial occurrence with
12516 <functionlink id="GenerateEvents"></functionlink>.
12517 </description>
12518 <origin>jvmpi</origin>
12519 <typedef id="jvmtiAddrLocationMap" label="Native address to location entry">
12520 <field id="start_address">
12521 <vmbuf><void/></vmbuf>
12522 <description>
12523 Starting native address of code corresponding to a location
12524 </description>
12525 </field>
12526 <field id="location">
12527 <jlocation/>
12528 <description>
12529 Corresponding location. See
12530 <functionlink id="GetJLocationFormat"></functionlink>
12531 for the meaning of location.
12532 </description>
12533 </field>
12534 </typedef>
12535 <capabilities>
12536 <required id="can_generate_compiled_method_load_events"></required>
12537 </capabilities>
12538 <parameters>
12539 <param id="klass">
12540 <jclass method="method"/>
12541 <description>
12542 Class of the method being compiled and loaded
12543 </description>
12544 </param>
12545 <param id="method">
12546 <jmethodID class="klass"/>
12547 <description>
12548 Method being compiled and loaded
12549 </description>
12550 </param>
12551 <param id="code_size">
12552 <jint/>
12553 <description>
12554 Size of compiled code
12555 </description>
12556 </param>
12557 <param id="code_addr">
12558 <vmbuf><void/></vmbuf>
12559 <description>
12560 Address where compiled method code is loaded
12561 </description>
12562 </param>
12563 <param id="map_length">
12564 <jint/>
12565 <description>
12566 Number of <typelink id="jvmtiAddrLocationMap"></typelink>
12567 entries in the address map.
12568 Zero if mapping information cannot be supplied.
12569 </description>
12570 </param>
12571 <param id="map">
12572 <vmbuf><struct>jvmtiAddrLocationMap</struct></vmbuf>
12573 <description>
12574 Map from native addresses to location.
12575 The native address range of each entry is from
12576 <fieldlink id="start_address" struct="jvmtiAddrLocationMap"></fieldlink>
12577 to <code>start_address-1</code> of the next entry.
12578 <code>NULL</code> if mapping information cannot be supplied.
12579 </description>
12580 </param>
12581 <param id="compile_info">
12582 <vmbuf><void/></vmbuf>
12583 <description>
12584 VM-specific compilation information.
12585 The referenced compile information is managed by the VM
12586 and must not depend on the agent for collection.
12587 A VM implementation defines the content and lifetime
12588 of the information.
12589 </description>
12590 </param>
12591 </parameters>
12592 </event>
12594 <event label="Compiled Method Unload"
12595 id="CompiledMethodUnload" const="JVMTI_EVENT_COMPILED_METHOD_UNLOAD" num="69">
12596 <description>
12597 Sent when a compiled method is unloaded from memory.
12598 This event might not be sent on the thread which performed the unload.
12599 This event may be sent sometime after the unload occurs, but
12600 will be sent before the memory is reused
12601 by a newly generated compiled method. This event may be sent after
12602 the class is unloaded.
12603 </description>
12604 <origin>jvmpi</origin>
12605 <capabilities>
12606 <required id="can_generate_compiled_method_load_events"></required>
12607 </capabilities>
12608 <parameters>
12609 <param id="klass">
12610 <jclass method="method"/>
12611 <description>
12612 Class of the compiled method being unloaded.
12613 </description>
12614 </param>
12615 <param id="method">
12616 <jmethodID class="klass"/>
12617 <description>
12618 Compiled method being unloaded.
12619 For identification of the compiled method only -- the class
12620 may be unloaded and therefore the method should not be used
12621 as an argument to further JNI or <jvmti/> functions.
12622 </description>
12623 </param>
12624 <param id="code_addr">
12625 <vmbuf><void/></vmbuf>
12626 <description>
12627 Address where compiled method code was loaded.
12628 For identification of the compiled method only --
12629 the space may have been reclaimed.
12630 </description>
12631 </param>
12632 </parameters>
12633 </event>
12635 <event label="Dynamic Code Generated" phase="any"
12636 id="DynamicCodeGenerated" const="JVMTI_EVENT_DYNAMIC_CODE_GENERATED" num="70">
12637 <description>
12638 Sent when a component of the virtual machine is generated dynamically.
12639 This does not correspond to Java programming language code that is
12640 compiled--see <eventlink id="CompiledMethodLoad"></eventlink>.
12641 This is for native code--for example, an interpreter that is generated
12642 differently depending on command-line options.
12643 <p/>
12644 Note that this event has no controlling capability.
12645 If a VM cannot generate these events, it simply does not send any.
12646 <p/>
12647 These events can be sent after their initial occurrence with
12648 <functionlink id="GenerateEvents"></functionlink>.
12649 </description>
12650 <origin>jvmpi</origin>
12651 <capabilities>
12652 </capabilities>
12653 <parameters>
12654 <param id="name">
12655 <vmbuf><char/></vmbuf>
12656 <description>
12657 Name of the code, encoded as a
12658 <internallink id="mUTF">modified UTF-8</internallink> string.
12659 Intended for display to an end-user.
12660 The name might not be unique.
12661 </description>
12662 </param>
12663 <param id="address">
12664 <vmbuf><void/></vmbuf>
12665 <description>
12666 Native address of the code
12667 </description>
12668 </param>
12669 <param id="length">
12670 <jint/>
12671 <description>
12672 Length in bytes of the code
12673 </description>
12674 </param>
12675 </parameters>
12676 </event>
12678 <event label="Data Dump Request"
12679 id="DataDumpRequest" const="JVMTI_EVENT_DATA_DUMP_REQUEST" num="71">
12680 <description>
12681 Sent by the VM to request the agent to dump its data. This
12682 is just a hint and the agent need not react to this event.
12683 This is useful for processing command-line signals from users. For
12684 example, in the Java 2 SDK a CTRL-Break on Win32 and a CTRL-\ on Solaris
12685 causes the VM to send this event to the agent.
12686 </description>
12687 <origin>jvmpi</origin>
12688 <capabilities>
12689 </capabilities>
12690 <parameters>
12691 </parameters>
12692 </event>
12694 <event label="Monitor Contended Enter"
12695 id="MonitorContendedEnter" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTER" filtered="thread" num="75">
12696 <description>
12697 Sent when a thread is attempting to enter a Java programming language
12698 monitor already acquired by another thread.
12699 </description>
12700 <origin>jvmpi</origin>
12701 <capabilities>
12702 <required id="can_generate_monitor_events"></required>
12703 </capabilities>
12704 <parameters>
12705 <param id="jni_env">
12706 <outptr>
12707 <struct>JNIEnv</struct>
12708 </outptr>
12709 <description>
12710 The JNI environment of the event (current) thread
12711 </description>
12712 </param>
12713 <param id="thread">
12714 <jthread/>
12715 <description>
12716 JNI local reference to the thread
12717 attempting to enter the monitor
12718 </description>
12719 </param>
12720 <param id="object">
12721 <jobject/>
12722 <description>
12723 JNI local reference to the monitor
12724 </description>
12725 </param>
12726 </parameters>
12727 </event>
12729 <event label="Monitor Contended Entered"
12730 id="MonitorContendedEntered" const="JVMTI_EVENT_MONITOR_CONTENDED_ENTERED" filtered="thread" num="76">
12731 <description>
12732 Sent when a thread enters a Java programming language
12733 monitor after waiting for it to be released by another thread.
12734 </description>
12735 <origin>jvmpi</origin>
12736 <capabilities>
12737 <required id="can_generate_monitor_events"></required>
12738 </capabilities>
12739 <parameters>
12740 <param id="jni_env">
12741 <outptr>
12742 <struct>JNIEnv</struct>
12743 </outptr>
12744 <description>
12745 The JNI environment of the event (current) thread
12746 </description>
12747 </param>
12748 <param id="thread">
12749 <jthread/>
12750 <description>
12751 JNI local reference to the thread entering
12752 the monitor
12753 </description>
12754 </param>
12755 <param id="object">
12756 <jobject/>
12757 <description>
12758 JNI local reference to the monitor
12759 </description>
12760 </param>
12761 </parameters>
12762 </event>
12764 <event label="Monitor Wait"
12765 id="MonitorWait" const="JVMTI_EVENT_MONITOR_WAIT" filtered="thread" num="73">
12766 <description>
12767 Sent when a thread is about to wait on an object.
12768 </description>
12769 <origin>jvmpi</origin>
12770 <capabilities>
12771 <required id="can_generate_monitor_events"></required>
12772 </capabilities>
12773 <parameters>
12774 <param id="jni_env">
12775 <outptr>
12776 <struct>JNIEnv</struct>
12777 </outptr>
12778 <description>
12779 The JNI environment of the event (current) thread
12780 </description>
12781 </param>
12782 <param id="thread">
12783 <jthread/>
12784 <description>
12785 JNI local reference to the thread about to wait
12786 </description>
12787 </param>
12788 <param id="object">
12789 <jobject/>
12790 <description>
12791 JNI local reference to the monitor
12792 </description>
12793 </param>
12794 <param id="timeout">
12795 <jlong/>
12796 <description>
12797 The number of milliseconds the thread will wait
12798 </description>
12799 </param>
12800 </parameters>
12801 </event>
12803 <event label="Monitor Waited"
12804 id="MonitorWaited" const="JVMTI_EVENT_MONITOR_WAITED" filtered="thread" num="74">
12805 <description>
12806 Sent when a thread finishes waiting on an object.
12807 </description>
12808 <origin>jvmpi</origin>
12809 <capabilities>
12810 <required id="can_generate_monitor_events"></required>
12811 </capabilities>
12812 <parameters>
12813 <param id="jni_env">
12814 <outptr>
12815 <struct>JNIEnv</struct>
12816 </outptr>
12817 <description>
12818 The JNI environment of the event (current) thread
12819 </description>
12820 </param>
12821 <param id="thread">
12822 <jthread/>
12823 <description>
12824 JNI local reference to the thread that was finished waiting
12825 </description>
12826 </param>
12827 <param id="object">
12828 <jobject/>
12829 <description>
12830 JNI local reference to the monitor.
12831 </description>
12832 </param>
12833 <param id="timed_out">
12834 <jboolean/>
12835 <description>
12836 True if the monitor timed out
12837 </description>
12838 </param>
12839 </parameters>
12840 </event>
12842 <event label="Resource Exhausted"
12843 id="ResourceExhausted" const="JVMTI_EVENT_RESOURCE_EXHAUSTED" num="80"
12844 since="1.1">
12845 <description>
12846 Sent when a VM resource needed by a running application has been exhausted.
12847 Except as required by the optional capabilities, the set of resources
12848 which report exhaustion is implementation dependent.
12849 <p/>
12850 The following bit flags define the properties of the resource exhaustion:
12851 <constants id="jvmtiResourceExhaustionFlags"
12852 label="Resource Exhaustion Flags"
12853 kind="bits"
12854 since="1.1">
12855 <constant id="JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR" num="0x0001">
12856 After this event returns, the VM will throw a
12857 <code>java.lang.OutOfMemoryError</code>.
12858 </constant>
12859 <constant id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP" num="0x0002">
12860 The VM was unable to allocate memory from the <tm>Java</tm>
12861 platform <i>heap</i>.
12862 The <i>heap</i> is the runtime
12863 data area from which memory for all class instances and
12864 arrays are allocated.
12865 </constant>
12866 <constant id="JVMTI_RESOURCE_EXHAUSTED_THREADS" num="0x0004">
12867 The VM was unable to create a thread.
12868 </constant>
12869 </constants>
12870 </description>
12871 <origin>new</origin>
12872 <capabilities>
12873 <capability id="can_generate_resource_exhaustion_heap_events">
12874 Can generate events when the VM is unable to allocate memory from the
12875 <internallink id="JVMTI_RESOURCE_EXHAUSTED_JAVA_HEAP">heap</internallink>.
12876 </capability>
12877 <capability id="can_generate_resource_exhaustion_threads_events">
12878 Can generate events when the VM is unable to
12879 <internallink id="JVMTI_RESOURCE_EXHAUSTED_THREADS">create
12880 a thread</internallink>.
12881 </capability>
12882 </capabilities>
12883 <parameters>
12884 <param id="jni_env">
12885 <outptr>
12886 <struct>JNIEnv</struct>
12887 </outptr>
12888 <description>
12889 The JNI environment of the event (current) thread
12890 </description>
12891 </param>
12892 <param id="flags">
12893 <jint/>
12894 <description>
12895 Flags defining the properties of the of resource exhaustion
12896 as specified by the
12897 <internallink id="jvmtiResourceExhaustionFlags">Resource
12898 Exhaustion Flags</internallink>.
12899 </description>
12900 </param>
12901 <param id="reserved">
12902 <vmbuf><void/></vmbuf>
12903 <description>
12904 Reserved.
12905 </description>
12906 </param>
12907 <param id="description">
12908 <vmbuf><char/></vmbuf>
12909 <description>
12910 Description of the resource exhaustion, encoded as a
12911 <internallink id="mUTF">modified UTF-8</internallink> string.
12912 </description>
12913 </param>
12914 </parameters>
12915 </event>
12917 <event label="VM Object Allocation"
12918 id="VMObjectAlloc" const="JVMTI_EVENT_VM_OBJECT_ALLOC" num="84">
12919 <description>
12920 Sent when a method causes the virtual machine to allocate an
12921 Object visible to Java programming language code and the
12922 allocation is not detectable by other intrumentation mechanisms.
12923 Generally object allocation should be detected by instrumenting
12924 the bytecodes of allocating methods.
12925 Object allocation generated in native code by JNI function
12926 calls should be detected using
12927 <internallink id="jniIntercept">JNI function interception</internallink>.
12928 Some methods might not have associated bytecodes and are not
12929 native methods, they instead are executed directly by the
12930 VM. These methods should send this event.
12931 Virtual machines which are incapable of bytecode instrumentation
12932 for some or all of their methods can send this event.
12933 <p/>
12934 Typical examples where this event might be sent:
12935 <ul>
12936 <li>Reflection -- for example, <code>java.lang.Class.newInstance()</code></li>
12937 <li>Methods not represented by bytecodes -- for example, VM intrinsics and
12938 J2ME preloaded classes</li>
12939 </ul>
12940 Cases where this event would not be generated:
12941 <ul>
12942 <li>Allocation due to bytecodes -- for example, the <code>new</code>
12943 and <code>newarray</code> VM instructions</li>
12944 <li>Allocation due to JNI function calls -- for example,
12945 <code>AllocObject</code></li>
12946 <li>Allocations during VM initialization</li>
12947 <li>VM internal objects</li>
12948 </ul>
12949 </description>
12950 <origin>new</origin>
12951 <capabilities>
12952 <required id="can_generate_vm_object_alloc_events"></required>
12953 </capabilities>
12954 <parameters>
12955 <param id="jni_env">
12956 <outptr>
12957 <struct>JNIEnv</struct>
12958 </outptr>
12959 <description>
12960 The JNI environment of the event (current) thread
12961 </description>
12962 </param>
12963 <param id="thread">
12964 <jthread/>
12965 <description>
12966 Thread allocating the object.
12967 </description>
12968 </param>
12969 <param id="object">
12970 <jobject/>
12971 <description>
12972 JNI local reference to the object that was allocated
12973 </description>
12974 </param>
12975 <param id="object_klass">
12976 <jclass/>
12977 <description>
12978 JNI local reference to the class of the object
12979 </description>
12980 </param>
12981 <param id="size">
12982 <jlong/>
12983 <description>
12984 Size of the object (in bytes). See <functionlink id="GetObjectSize"/>.
12985 </description>
12986 </param>
12987 </parameters>
12988 </event>
12990 <event label="Object Free"
12991 id="ObjectFree" const="JVMTI_EVENT_OBJECT_FREE" num="83">
12992 <description>
12993 An Object Free event is sent when the garbage collector frees an object.
12994 Events are only sent for tagged objects--see
12995 <internallink id="Heap">heap functions</internallink>.
12996 <p/>
12997 The event handler must not use JNI functions and
12998 must not use <jvmti/> functions except those which
12999 specifically allow such use (see the raw monitor, memory management,
13000 and environment local storage functions).
13001 </description>
13002 <origin>new</origin>
13003 <capabilities>
13004 <required id="can_generate_object_free_events"></required>
13005 </capabilities>
13006 <parameters>
13007 <param id="tag">
13008 <jlong/>
13009 <description>
13010 The freed object's tag
13011 </description>
13012 </param>
13013 </parameters>
13014 </event>
13016 <event label="Garbage Collection Start"
13017 id="GarbageCollectionStart" const="JVMTI_EVENT_GARBAGE_COLLECTION_START" num="81">
13018 <description>
13019 A Garbage Collection Start event is sent when a
13020 garbage collection pause begins.
13021 Only stop-the-world collections are reported--that is, collections during
13022 which all threads cease to modify the state of the Java virtual machine.
13023 This means that some collectors will never generate these events.
13024 This event is sent while the VM is still stopped, thus
13025 the event handler must not use JNI functions and
13026 must not use <jvmti/> functions except those which
13027 specifically allow such use (see the raw monitor, memory management,
13028 and environment local storage functions).
13029 <p/>
13030 This event is always sent as a matched pair with
13031 <eventlink id="GarbageCollectionFinish"/>
13032 (assuming both events are enabled) and no garbage collection
13033 events will occur between them.
13034 </description>
13035 <origin>new</origin>
13036 <capabilities>
13037 <required id="can_generate_garbage_collection_events"></required>
13038 </capabilities>
13039 <parameters>
13040 </parameters>
13041 </event>
13043 <event label="Garbage Collection Finish"
13044 id="GarbageCollectionFinish" const="JVMTI_EVENT_GARBAGE_COLLECTION_FINISH" num="82">
13045 <description>
13046 A Garbage Collection Finish event is sent when a
13047 garbage collection pause ends.
13048 This event is sent while the VM is still stopped, thus
13049 the event handler must not use JNI functions and
13050 must not use <jvmti/> functions except those which
13051 specifically allow such use (see the raw monitor, memory management,
13052 and environment local storage functions).
13053 <p/>
13054 Some agents may need to do post garbage collection operations that
13055 require the use of the disallowed <jvmti/> or JNI functions. For these
13056 cases an agent thread can be created which waits on a raw monitor,
13057 and the handler for the Garbage Collection Finish event simply
13058 notifies the raw monitor
13059 <p/>
13060 This event is always sent as a matched pair with
13061 <eventlink id="GarbageCollectionStart"/> (assuming both events are enabled).
13062 <issue>
13063 The most important use of this event is to provide timing information,
13064 and thus additional information is not required. However,
13065 information about the collection which is "free" should be included -
13066 what that information is needs to be determined.
13067 </issue>
13068 </description>
13069 <origin>new</origin>
13070 <capabilities>
13071 <required id="can_generate_garbage_collection_events"></required>
13072 </capabilities>
13073 <parameters>
13074 </parameters>
13075 </event>
13077 <elide>
13078 <event label="Verbose Output" phase="any"
13079 id="VerboseOutput" const="JVMTI_EVENT_VERBOSE_OUTPUT" num="85">
13080 <description>
13081 Send verbose messages as strings.
13082 <issue>
13083 This format is extremely fragile, as it can change with each
13084 platform, collector and version. Alternatives include:
13085 <ul>
13086 <li>building off Java programming language M and M APIs</li>
13087 <li>XML</li>
13088 <li>key/value pairs</li>
13089 <li>removing it</li>
13090 </ul>
13091 </issue>
13092 <issue>
13093 Though this seemed trivial to implement.
13094 In the RI it appears this will be quite complex.
13095 </issue>
13096 </description>
13097 <origin>new</origin>
13098 <capabilities>
13099 </capabilities>
13100 <parameters>
13101 <param id="flag">
13102 <enum>jvmtiVerboseFlag</enum>
13103 <description>
13104 Which verbose output is being sent.
13105 </description>
13106 </param>
13107 <param id="message">
13108 <vmbuf><char/></vmbuf>
13109 <description>
13110 Message text, encoded as a
13111 <internallink id="mUTF">modified UTF-8</internallink> string.
13112 </description>
13113 </param>
13114 </parameters>
13115 </event>
13116 </elide>
13118 </eventsection>
13120 <datasection>
13121 <intro>
13122 <jvmti/> extends the data types defined by JNI.
13123 </intro>
13124 <basetypes id="jniTypes" label="JNI Types Used in the JVM Tool Interface">
13125 <basetype id="jboolean">
13126 <description>
13127 Holds a Java programming language <code>boolean</code>.
13128 Unsigned 8 bits.
13129 </description>
13130 </basetype>
13131 <basetype id="jint">
13132 <description>
13133 Holds a Java programming language <code>int</code>.
13134 Signed 32 bits.
13135 </description>
13136 </basetype>
13137 <basetype id="jlong">
13138 <description>
13139 Holds a Java programming language <code>long</code>.
13140 Signed 64 bits.
13141 </description>
13142 </basetype>
13143 <basetype id="jfloat">
13144 <description>
13145 Holds a Java programming language <code>float</code>.
13146 32 bits.
13147 </description>
13148 </basetype>
13149 <basetype id="jdouble">
13150 <description>
13151 Holds a Java programming language <code>double</code>.
13152 64 bits.
13153 </description>
13154 </basetype>
13155 <basetype id="jobject">
13156 <description>
13157 Holds a Java programming language object.
13158 </description>
13159 </basetype>
13160 <basetype id="jclass">
13161 <description>
13162 Holds a Java programming language class.
13163 </description>
13164 </basetype>
13165 <basetype id="jvalue">
13166 <description>
13167 Is a union of all primitive types and <code>jobject</code>. Thus, holds any Java
13168 programming language value.
13169 </description>
13170 </basetype>
13171 <basetype id="jfieldID">
13172 <description>
13173 Identifies a Java programming language field.
13174 <code>jfieldID</code>s returned by <jvmti/> functions and events may be
13175 safely stored.
13176 </description>
13177 </basetype>
13178 <basetype id="jmethodID">
13179 <description>
13180 Identifies a Java programming language method, initializer, or constructor.
13181 <code>jmethodID</code>s returned by <jvmti/> functions and events may be
13182 safely stored. However, if the class is unloaded, they become invalid
13183 and must not be used.
13184 </description>
13185 </basetype>
13186 <basetype id="JNIEnv">
13187 <description>
13188 Pointer to the JNI function table. Pointer to this (<code>JNIEnv *</code>)
13189 is a JNI environment.
13190 </description>
13191 </basetype>
13192 </basetypes>
13194 <basetypes id="jvmtiTypes" label="JVM Tool Interface Base Types">
13195 <basetype id="jvmtiEnv">
13196 <description>
13197 The <jvmti/> <internallink id="environments">environment</internallink> pointer.
13198 See the <internallink id="FunctionSection">Function Section</internallink>.
13199 <code>jvmtiEnv</code> points to the
13200 <internallink id="FunctionTable">function table</internallink> pointer.
13201 </description>
13202 </basetype>
13203 <basetype id="jthread">
13204 <definition>typedef jobject jthread;</definition>
13205 <description>
13206 Subtype of <datalink id="jobject"></datalink> that holds a thread.
13207 </description>
13208 </basetype>
13209 <basetype id="jthreadGroup">
13210 <definition>typedef jobject jthreadGroup;</definition>
13211 <description>
13212 Subtype of <datalink id="jobject"></datalink> that holds a thread group.
13213 </description>
13214 </basetype>
13215 <basetype id="jlocation">
13216 <definition>typedef jlong jlocation;</definition>
13217 <description>
13218 A 64 bit value, representing a monotonically increasing
13219 executable position within a method.
13220 <code>-1</code> indicates a native method.
13221 See <functionlink id="GetJLocationFormat"></functionlink> for the format on a
13222 given VM.
13223 </description>
13224 </basetype>
13225 <basetype id="jrawMonitorID">
13226 <definition>struct _jrawMonitorID;
13227 typedef struct _jrawMonitorID *jrawMonitorID;</definition>
13228 <description>
13229 A raw monitor.
13230 </description>
13231 </basetype>
13232 <basetype id="jvmtiError">
13233 <description>
13234 Holds an error return code.
13235 See the <internallink id="ErrorSection">Error section</internallink> for possible values.
13236 <example>
13237 typedef enum {
13238 JVMTI_ERROR_NONE = 0,
13239 JVMTI_ERROR_INVALID_THREAD = 10,
13240 ...
13241 } jvmtiError;
13242 </example>
13243 </description>
13244 </basetype>
13245 <basetype id="jvmtiEvent">
13246 <description>
13247 An identifier for an event type.
13248 See the <internallink id="EventSection">Event section</internallink> for possible values.
13249 It is guaranteed that future versions of this specification will
13250 never assign zero as an event type identifier.
13251 <example>
13252 typedef enum {
13253 JVMTI_EVENT_SINGLE_STEP = 1,
13254 JVMTI_EVENT_BREAKPOINT = 2,
13255 ...
13256 } jvmtiEvent;
13257 </example>
13258 </description>
13259 </basetype>
13260 <basetype id="jvmtiEventCallbacks">
13261 <description>
13262 The callbacks used for events.
13263 <example>
13264 typedef struct {
13265 jvmtiEventVMInit VMInit;
13266 jvmtiEventVMDeath VMDeath;
13267 ...
13268 } jvmtiEventCallbacks;
13269 </example>
13270 See <internallink id="jvmtiEventCallbacks">event callbacks</internallink>
13271 for the complete structure.
13272 <p/>
13273 Where, for example, the VM initialization callback is defined:
13274 <example>
13275 typedef void (JNICALL *jvmtiEventVMInit)
13276 (jvmtiEnv *jvmti_env,
13277 JNIEnv* jni_env,
13278 jthread thread);
13279 </example>
13280 See the individual events for the callback function definition.
13281 </description>
13282 </basetype>
13283 <basetype id="jniNativeInterface">
13284 <definition>typedef struct JNINativeInterface_ jniNativeInterface;</definition>
13285 <description>
13286 Typedef for the JNI function table <code>JNINativeInterface</code>
13287 defined in the
13288 <externallink id="http://java.sun.com/javase/6/docs/guide/jni/spec/functions.html#wp23720">JNI Specification</externallink>.
13289 The JNI reference implementation defines this with an underscore.
13290 </description>
13291 </basetype>
13292 </basetypes>
13294 </datasection>
13296 <issuessection label="Issues">
13297 <intro id="suspendRequired" label="Resolved Issue: Suspend - Required or Automatic">
13298 JVMDI requires that the agent suspend threads before calling
13299 certain sensitive functions. JVMPI requires garbage collection to be
13300 disabled before calling certain sensitive functions.
13301 It was suggested that rather than have this requirement, that
13302 VM place itself in a suitable state before performing an
13303 operation. This makes considerable sense since each VM
13304 knows its requirements and can most easily arrange a
13305 safe state.
13306 <p/>
13307 The ability to externally suspend/resume threads will, of
13308 course, remain. The ability to enable/disable garbage collection will not.
13309 <p/>
13310 This issue is resolved--suspend will not
13311 be required. The spec has been updated to reflect this.
13312 </intro>
13314 <intro id="stackSampling" label="Resolved Issue: Call Stack Sampling">
13315 There are a variety of approaches to sampling call stacks.
13316 The biggest bifurcation is between VM controlled and agent
13317 controlled.
13318 <p/>
13319 This issue is resolved--agent controlled
13320 sampling will be the approach.
13321 </intro>
13323 <intro id="threadRepresentation" label="Resolved Issue: Thread Representation">
13324 JVMDI represents threads as jthread. JVMPI primarily
13325 uses JNIEnv* to represent threads.
13326 <p/>
13327 The Expert Group has chosen jthread as the representation
13328 for threads in <jvmti/>.
13329 JNIEnv* is sent by
13330 events since it is needed to JNI functions. JNIEnv, per the
13331 JNI spec, are not supposed to be used outside their thread.
13332 </intro>
13334 <intro id="design" label="Resolved Issue: Method Representation">
13335 The JNI spec allows an implementation to depend on jclass/jmethodID
13336 pairs, rather than simply a jmethodID, to reference a method.
13337 JVMDI, for consistency, choose the same representation.
13338 JVMPI, however, specifies that a jmethodID alone maps to a
13339 method. Both of the Sun <tm>J2SE</tm> virtual machines (Classic and <tm>HotSpot</tm>) store
13340 pointers in jmethodIDs, and as a result, a jmethodID is sufficient.
13341 In fact, any JVM implementation that supports JVMPI must have
13342 such a representation.
13343 <jvmti/> will use jmethodID as a unique representation of a method
13344 (no jclass is used).
13345 There should be efficiency gains, particularly in
13346 functionality like stack dumping, to this representation.
13347 <p/>
13348 Note that fields were not used in JVMPI and that the access profile
13349 of fields differs from methods--for implementation efficiency
13350 reasons, a jclass/jfieldID pair will still be needed for field
13351 reference.
13352 </intro>
13354 <intro id="localReferenceIssue" label="Resolved Issue: Local References">
13355 Functions return local references.
13356 </intro>
13358 <intro id="frameRep" label="Resolved Issue: Representation of frames">
13359 In JVMDI, a frame ID is used to represent a frame. Problem with this
13360 is that a VM must track when a frame becomes invalid, a far better
13361 approach, and the one used in <jvmti/>, is to reference frames by depth.
13362 </intro>
13364 <intro id="requiredCapabilities" label="Issue: Required Capabilities">
13365 Currently, having a required capabilities means that the functionality
13366 is optional. Capabilities are useful even for required functionality
13367 since they can inform the VM is needed set-up. Thus, there should be
13368 a set of capabilities that a conformant implementation must provide
13369 (if requested during Agent_OnLoad).
13370 </intro>
13372 <intro id="taghint" label="Proposal: add tag hint function">
13373 A hint of the percentage of objects that will be tagged would
13374 help the VM pick a good implementation.
13375 </intro>
13377 <intro id="moreMonitorQueries" label="Request: More Monitor Quires">
13378 How difficult or easy would be to extend the monitor_info category to include
13379 <pre>
13380 - current number of monitors
13381 - enumeration of monitors
13382 - enumeration of threads waiting on a given monitor
13383 </pre>
13384 The reason for my question is the fact that current get_monitor_info support
13385 requires the agent to specify a given thread to get the info which is probably
13386 OK in the profiling/debugging space, while in the monitoring space the agent
13387 could be watching the monitor list and then decide which thread to ask for
13388 the info. You might ask why is this important for monitoring .... I think it
13389 can aid in the detection/prediction of application contention caused by hot-locks.
13390 </intro>
13391 </issuessection>
13393 <changehistory id="ChangeHistory" update="09/05/07">
13394 <intro>
13395 The <jvmti/> specification is an evolving document with major, minor,
13396 and micro version numbers.
13397 A released version of the specification is uniquely identified
13398 by its major and minor version.
13399 The functions, events, and capabilities in this specification
13400 indicate a "Since" value which is the major and minor version in
13401 which it was introduced.
13402 The version of the specification implemented by the VM can
13403 be retrieved at runtime with the <functionlink id="GetVersionNumber"/>
13404 function.
13405 </intro>
13406 <change date="14 Nov 2002">
13407 Converted to XML document.
13408 </change>
13409 <change date="14 Nov 2002">
13410 Elided heap dump functions (for now) since what was there
13411 was wrong.
13412 </change>
13413 <change date="18 Nov 2002">
13414 Added detail throughout.
13415 </change>
13416 <change date="18 Nov 2002">
13417 Changed JVMTI_THREAD_STATUS_RUNNING to JVMTI_THREAD_STATUS_RUNNABLE.
13418 </change>
13419 <change date="19 Nov 2002">
13420 Added AsyncGetStackTrace.
13421 </change>
13422 <change date="19 Nov 2002">
13423 Added jframeID return to GetStackTrace.
13424 </change>
13425 <change date="19 Nov 2002">
13426 Elided GetCurrentFrame and GetCallingFrame functions (for now) since what was there
13427 since they are redundant with GetStackTrace.
13428 </change>
13429 <change date="19 Nov 2002">
13430 Elided ClearAllBreakpoints since it has always been redundant.
13431 </change>
13432 <change date="19 Nov 2002">
13433 Added GetSystemProperties.
13434 </change>
13435 <change date="19 Nov 2002">
13436 Changed the thread local storage functions to use jthread.
13437 </change>
13438 <change date="20 Nov 2002">
13439 Added GetJLocationFormat.
13440 </change>
13441 <change date="22 Nov 2002">
13442 Added events and introductory text.
13443 </change>
13444 <change date="22 Nov 2002">
13445 Cross reference type and constant definitions.
13446 </change>
13447 <change date="24 Nov 2002">
13448 Added DTD.
13449 </change>
13450 <change date="24 Nov 2002">
13451 Added capabilities function section.
13452 </change>
13453 <change date="29 Nov 2002">
13454 Assign capabilities to each function and event.
13455 </change>
13456 <change date="29 Nov 2002">
13457 Add <internallink id="jniIntercept">JNI interception functions</internallink>.
13458 </change>
13459 <change date="30 Nov 2002">
13460 Auto generate SetEventNotificationMode capabilities.
13461 </change>
13462 <change date="30 Nov 2002">
13463 Add <eventlink id="VMObjectAlloc"></eventlink> event.
13464 </change>
13465 <change date="30 Nov 2002">
13466 Add <eventlink id="DynamicCodeGenerated"></eventlink> event.
13467 </change>
13468 <change date="30 Nov 2002">
13469 Add const to declarations.
13470 </change>
13471 <change date="30 Nov 2002">
13472 Change method exit and frame pop to send on exception.
13473 </change>
13474 <change date="1 Dec 2002">
13475 Add ForceGarbageCollection.
13476 </change>
13477 <change date="2 Dec 2002">
13478 Redo Xrun section; clarify GetStackTrace and add example;
13479 Fix width problems; use "agent" consistently.
13480 </change>
13481 <change date="8 Dec 2002">
13482 Remove previous start-up intro.
13483 Add <internallink id="environments"><jvmti/> Environments</internallink>
13484 section.
13485 </change>
13486 <change date="8 Dec 2002">
13487 Add <functionlink id="DisposeEnvironment"></functionlink>.
13488 </change>
13489 <change date="9 Dec 2002">
13490 Numerous minor updates.
13491 </change>
13492 <change date="15 Dec 2002">
13493 Add heap profiling functions added:
13494 get/set annotation, iterate live objects/heap.
13495 Add heap profiling functions place holder added:
13496 heap roots.
13497 Heap profiling event added: object free.
13498 Heap profiling event redesigned: vm object allocation.
13499 Heap profiling event placeholders added: garbage collection start/finish.
13500 Native method bind event added.
13501 </change>
13502 <change date="19 Dec 2002">
13503 Revamp suspend/resume functions.
13504 Add origin information with jvmdi tag.
13505 Misc fixes.
13506 </change>
13507 <change date="24 Dec 2002">
13508 Add semantics to types.
13509 </change>
13510 <change date="27 Dec 2002">
13511 Add local reference section.
13512 Autogenerate parameter descriptions from types.
13513 </change>
13514 <change date="28 Dec 2002">
13515 Document that RunAgentThread sends threadStart.
13516 </change>
13517 <change date="29 Dec 2002">
13518 Remove redundant local ref and dealloc warning.
13519 Convert GetRawMonitorName to allocated buffer.
13520 Add GenerateEvents.
13521 </change>
13522 <change date="30 Dec 2002">
13523 Make raw monitors a type and rename to "jrawMonitorID".
13524 </change>
13525 <change date="1 Jan 2003">
13526 Include origin information.
13527 Clean-up JVMDI issue references.
13528 Remove Deallocate warnings which are now automatically generated.
13529 </change>
13530 <change date="2 Jan 2003">
13531 Fix representation issues for jthread.
13532 </change>
13533 <change date="3 Jan 2003">
13534 Make capabilities buffered out to 64 bits - and do it automatically.
13535 </change>
13536 <change date="4 Jan 2003">
13537 Make constants which are enumeration into enum types.
13538 Parameters now of enum type.
13539 Clean-up and index type section.
13540 Replace remaining datadef entities with callback.
13541 </change>
13542 <change date="7 Jan 2003">
13543 Correct GenerateEvents description.
13544 More internal semantics work.
13545 </change>
13546 <change date="9 Jan 2003">
13547 Replace previous GetSystemProperties with two functions
13548 which use allocated information instead fixed.
13549 Add SetSystemProperty.
13550 More internal semantics work.
13551 </change>
13552 <change date="12 Jan 2003">
13553 Add varargs to end of SetEventNotificationMode.
13554 </change>
13555 <change date="20 Jan 2003">
13556 Finish fixing spec to reflect that alloc sizes are jlong.
13557 </change>
13558 <change date="22 Jan 2003">
13559 Allow NULL as RunAgentThread arg.
13560 </change>
13561 <change date="22 Jan 2003">
13562 Fixed names to standardized naming convention
13563 Removed AsyncGetStackTrace.
13564 </change>
13565 <change date="29 Jan 2003">
13566 Since we are using jthread, removed GetThread.
13567 </change>
13568 <change date="31 Jan 2003">
13569 Change GetFieldName to allow NULLs like GetMethodName.
13570 </change>
13571 <change date="29 Feb 2003" version="v40">
13572 Rewrite the introductory text, adding sections on
13573 start-up, environments and bytecode instrumentation.
13574 Change the command line arguments per EG discussions.
13575 Add an introduction to the capabilities section.
13576 Add the extension mechanism category and functions.
13577 Mark for deletion, but clarified anyhow, SuspendAllThreads.
13578 Rename IterateOverLiveObjects to IterateOverReachableObjects and
13579 change the text accordingly.
13580 Clarify IterateOverHeap.
13581 Clarify CompiledMethodLoad.
13582 Discuss prerequisite state for Calling Functions.
13583 Clarify SetAllocationHooks.
13584 Added issues ("To be resolved:") through-out.
13585 And so on...
13586 </change>
13587 <change date="6 Mar 2003" version="v41">
13588 Remove struct from the call to GetOwnedMonitorInfo.
13589 Automatically generate most error documentation, remove
13590 (rather broken) hand written error doc.
13591 Better describe capability use (empty initial set).
13592 Add min value to jint params.
13593 Remove the capability can_access_thread_local_storage.
13594 Rename error JVMTI_ERROR_NOT_IMPLEMENTED to JVMTI_ERROR_MUST_POSSESS_CAPABILITY;
13595 same for *NOT_IMPLEMENTED.
13596 Description fixes.
13597 </change>
13598 <change date="8 Mar 2003" version="v42">
13599 Rename GetClassSignature to GetClassName.
13600 Rename IterateOverClassObjects to IterateOverInstancesOfClass.
13601 Remove GetMaxStack (operand stack isn't used in <jvmti/>).
13602 Description fixes: define launch-time, remove native frame pop
13603 from PopFrame, and assorted clarifications.
13604 </change>
13605 <change date="8 Mar 2003" version="v43">
13606 Fix minor editing problem.
13607 </change>
13608 <change date="10 Mar 2003" version="v44">
13609 Add phase information.
13610 Remap (compact) event numbers.
13611 </change>
13612 <change date="11 Mar 2003" version="v45">
13613 More phase information - allow "any".
13614 Elide raw monitor queries and events.
13615 Minor description fixes.
13616 </change>
13617 <change date="12 Mar 2003" version="v46">
13618 Add GetPhase.
13619 Use "phase" through document.
13620 Elide GetRawMonitorName.
13621 Elide GetObjectMonitors.
13622 </change>
13623 <change date="12 Mar 2003" version="v47">
13624 Fixes from link, XML, and spell checking.
13625 Auto-generate the callback structure.
13626 </change>
13627 <change date="13 Mar 2003" version="v48">
13628 One character XML fix.
13629 </change>
13630 <change date="13 Mar 2003" version="v49">
13631 Change function parameter names to be consistent with
13632 event parameters (fooBarBaz becomes foo_bar_baz).
13633 </change>
13634 <change date="14 Mar 2003" version="v50">
13635 Fix broken link. Fix thread markers.
13636 </change>
13637 <change date="14 Mar 2003" version="v51">
13638 Change constants so they are under 128 to workaround
13639 compiler problems.
13640 </change>
13641 <change date="23 Mar 2003" version="v52">
13642 Overhaul capabilities. Separate GetStackTrace into
13643 GetStackTrace and GetStackFrames.
13644 </change>
13645 <change date="8 Apr 2003" version="v54">
13646 Use depth instead of jframeID to reference frames.
13647 Remove the now irrelevant GetCurrentFrame, GetCallerFrame and GetStackFrames.
13648 Remove frame arg from events.
13649 </change>
13650 <change date="9 Apr 2003" version="v55">
13651 Remove GetObjectWithAnnotation since tests show bufferred approach more efficient.
13652 Add missing annotation_count to GetObjectsWithAnnotations
13653 </change>
13654 <change date="10 Apr 2003" version="v56">
13655 Remove confusing parenthetical statement in GetObjectsWithAnnotations
13656 </change>
13657 <change date="13 Apr 2003" version="v58">
13658 Replace jclass/jmethodID representation of method with simply jmethodID;
13659 Pass JvmtiEnv* as first arg of every event; remove JNIEnv* where inappropriate.
13660 Replace can_access_frames with can_access_local_variables; remove from purely stack access.
13661 Use can_get_synthetic_attribute; fix description.
13662 Clarify that zero length arrays must be deallocated.
13663 Clarify RelinquishCapabilities.
13664 Generalize JVMTI_ERROR_VM_DEAD to JVMTI_ERROR_WRONG_PHASE.
13665 </change>
13666 <change date="27 Apr 2003" version="v59">
13667 Remove lingering indirect references to OBSOLETE_METHOD_ID.
13668 </change>
13669 <change date="4 May 2003" version="v60">
13670 Allow DestroyRawMonitor during OnLoad.
13671 </change>
13672 <change date="7 May 2003" version="v61">
13673 Added not monitor owner error return to DestroyRawMonitor.
13674 </change>
13675 <change date="13 May 2003" version="v62">
13676 Clarify semantics of raw monitors.
13677 Change flags on <code>GetThreadStatus</code>.
13678 <code>GetClassLoader</code> return NULL for the bootstrap class loader.
13679 Add <code>GetClassName</code> issue.
13680 Define local variable signature.
13681 Disallow zero in annotations array of <code>GetObjectsWithAnnotations</code>.
13682 Remove over specification in <code>GetObjectsWithAnnotations</code>.
13683 Elide <code>SetAllocationHooks</code>.
13684 Elide <code>SuspendAllThreads</code>.
13685 </change>
13686 <change date="14 May 2003" version="v63">
13687 Define the data type <code>jvmtiEventCallbacks</code>.
13688 Zero length allocations return NULL.
13689 Keep SetAllocationHooks in JVMDI, but remove from <jvmti/>.
13690 Add JVMTI_THREAD_STATUS_FLAG_INTERRUPTED.
13691 </change>
13692 <change date="15 May 2003" version="v64">
13693 Better wording, per review.
13694 </change>
13695 <change date="15 May 2003" version="v65">
13696 First Alpha.
13697 Make jmethodID and jfieldID unique, jclass not used.
13698 </change>
13699 <change date="27 May 2003" version="v66">
13700 Fix minor XSLT errors.
13701 </change>
13702 <change date="13 June 2003" version="v67">
13703 Undo making jfieldID unique (jmethodID still is).
13704 </change>
13705 <change date="17 June 2003" version="v68">
13706 Changes per June 11th Expert Group meeting --
13707 Overhaul Heap functionality: single callback,
13708 remove GetHeapRoots, add reachable iterators,
13709 and rename "annotation" to "tag".
13710 NULL thread parameter on most functions is current
13711 thread.
13712 Add timers.
13713 Remove ForceExit.
13714 Add GetEnvironmentLocalStorage.
13715 Add verbose flag and event.
13716 Add AddToBootstrapClassLoaderSearch.
13717 Update ClassFileLoadHook.
13718 </change>
13719 <change date="18 June 2003" version="v69">
13720 Clean up issues sections.
13721 Rename GetClassName back to GetClassSignature and
13722 fix description.
13723 Add generic signature to GetClassSignature,
13724 GetFieldSignature, GetMethodSignature, and
13725 GetLocalVariableTable.
13726 Elide EstimateCostOfCapabilities.
13727 Clarify that the system property functions operate
13728 on the VM view of system properties.
13729 Clarify Agent_OnLoad.
13730 Remove "const" from JNIEnv* in events.
13731 Add metadata accessors.
13732 </change>
13733 <change date="18 June 2003" version="v70">
13734 Add start_depth to GetStackTrace.
13735 Move system properties to a new category.
13736 Add GetObjectSize.
13737 Remove "X" from command line flags.
13738 XML, HTML, and spell check corrections.
13739 </change>
13740 <change date="19 June 2003" version="v71">
13741 Fix JVMTI_HEAP_ROOT_THREAD to be 6.
13742 Make each synopsis match the function name.
13743 Fix unclear wording.
13744 </change>
13745 <change date="26 June 2003" version="v72">
13746 SetThreadLocalStorage and SetEnvironmentLocalStorage should allow value
13747 to be set to NULL.
13748 NotifyFramePop, GetFrameLocationm and all the local variable operations
13749 needed to have their wording about frames fixed.
13750 Grammar and clarity need to be fixed throughout.
13751 Capitalization and puntuation need to be consistent.
13752 Need micro version number and masks for accessing major, minor, and micro.
13753 The error code lists should indicate which must be returned by
13754 an implementation.
13755 The command line properties should be visible in the properties functions.
13756 Disallow popping from the current thread.
13757 Allow implementations to return opaque frame error when they cannot pop.
13758 The NativeMethodBind event should be sent during any phase.
13759 The DynamicCodeGenerated event should be sent during any phase.
13760 The following functions should be allowed to operate before VMInit:
13761 Set/GetEnvironmentLocalStorage
13762 GetMethodDeclaringClass
13763 GetClassSignature
13764 GetClassModifiers
13765 IsInterface
13766 IsArrayClass
13767 GetMethodName
13768 GetMethodModifiers
13769 GetMaxLocals
13770 GetArgumentsSize
13771 GetLineNumberTable
13772 GetMethodLocation
13773 IsMethodNative
13774 IsMethodSynthetic.
13775 Other changes (to XSL):
13776 Argument description should show asterisk after not before pointers.
13777 NotifyFramePop, GetFrameLocationm and all the local variable operations
13778 should hsve the NO_MORE_FRAMES error added.
13779 Not alive threads should have a different error return than invalid thread.
13780 </change>
13781 <change date="7 July 2003" version="v73">
13782 VerboseOutput event was missing message parameter.
13783 Minor fix-ups.
13784 </change>
13785 <change date="14 July 2003" version="v74">
13786 Technical Publications Department corrections.
13787 Allow thread and environment local storage to be set to NULL.
13788 </change>
13789 <change date="23 July 2003" version="v75">
13790 Use new Agent_OnLoad rather than overloaded JVM_OnLoad.
13791 Add JNICALL to callbacks (XSL).
13792 Document JNICALL requirement for both events and callbacks (XSL).
13793 Restrict RedefineClasses to methods and attributes.
13794 Elide the VerboseOutput event.
13795 VMObjectAlloc: restrict when event is sent and remove method parameter.
13796 Finish loose ends from Tech Pubs edit.
13797 </change>
13798 <change date="24 July 2003" version="v76">
13799 Change ClassFileLoadHook event to send the class instead of a boolean of redefine.
13800 </change>
13801 <change date="24 July 2003" version="v77">
13802 XML fixes.
13803 Minor text clarifications and corrections.
13804 </change>
13805 <change date="24 July 2003" version="v78">
13806 Remove GetExceptionHandlerTable and GetThrownExceptions from <jvmti/>.
13807 Clarify that stack frames are JVM Spec frames.
13808 Split can_get_source_info into can_get_source_file_name, can_get_line_numbers,
13809 and can_get_source_debug_extension.
13810 PopFrame cannot have a native calling method.
13811 Removed incorrect statement in GetClassloaderClasses
13812 (see <vmspec chapter="4.4"/>).
13813 </change>
13814 <change date="24 July 2003" version="v79">
13815 XML and text fixes.
13816 Move stack frame description into Stack Frame category.
13817 </change>
13818 <change date="26 July 2003" version="v80">
13819 Allow NULL (means bootstrap loader) for GetClassloaderClasses.
13820 Add new heap reference kinds for references from classes.
13821 Add timer information struct and query functions.
13822 Add AvailableProcessors.
13823 Rename GetOtherThreadCpuTime to GetThreadCpuTime.
13824 Explicitly add JVMTI_ERROR_INVALID_THREAD and JVMTI_ERROR_THREAD_NOT_ALIVE
13825 to SetEventNotification mode.
13826 Add initial thread to the VM_INIT event.
13827 Remove platform assumptions from AddToBootstrapClassLoaderSearch.
13828 </change>
13829 <change date="26 July 2003" version="v81">
13830 Grammar and clarity changes per review.
13831 </change>
13832 <change date="27 July 2003" version="v82">
13833 More grammar and clarity changes per review.
13834 Add Agent_OnUnload.
13835 </change>
13836 <change date="28 July 2003" version="v83">
13837 Change return type of Agent_OnUnload to void.
13838 </change>
13839 <change date="28 July 2003" version="v84">
13840 Rename JVMTI_REFERENCE_ARRAY to JVMTI_REFERENCE_ARRAY_ELEMENT.
13841 </change>
13842 <change date="28 July 2003" version="v85">
13843 Steal java.lang.Runtime.availableProcessors() wording for
13844 AvailableProcessors().
13845 Guarantee that zero will never be an event ID.
13846 Remove some issues which are no longer issues.
13847 Per review, rename and more completely document the timer
13848 information functions.
13849 </change>
13850 <change date="29 July 2003" version="v86">
13851 Non-spec visible change to XML controlled implementation:
13852 SetThreadLocalStorage must run in VM mode.
13853 </change>
13854 <change date="5 August 2003" version="0.1.87">
13855 Add GetErrorName.
13856 Add varargs warning to jvmtiExtensionEvent.
13857 Remove "const" on the jvmtiEnv* of jvmtiExtensionEvent.
13858 Remove unused can_get_exception_info capability.
13859 Pass jvmtiEnv* and JNIEnv* to the jvmtiStartFunction.
13860 Fix jvmtiExtensionFunctionInfo.func declared type.
13861 Extension function returns error code.
13862 Use new version numbering.
13863 </change>
13864 <change date="5 August 2003" version="0.2.88">
13865 Remove the ClassUnload event.
13866 </change>
13867 <change date="8 August 2003" version="0.2.89">
13868 Heap reference iterator callbacks return an enum that
13869 allows outgoing object references to be ignored.
13870 Allow JNIEnv as a param type to extension events/functions.
13871 </change>
13872 <change date="15 August 2003" version="0.2.90">
13873 Fix a typo.
13874 </change>
13875 <change date="2 September 2003" version="0.2.91">
13876 Remove all metadata functions: GetClassMetadata,
13877 GetFieldMetadata, and GetMethodMetadata.
13878 </change>
13879 <change date="1 October 2003" version="0.2.92">
13880 Mark the functions Allocate. Deallocate, RawMonitor*,
13881 SetEnvironmentLocalStorage, and GetEnvironmentLocalStorage
13882 as safe for use in heap callbacks and GC events.
13883 </change>
13884 <change date="24 November 2003" version="0.2.93">
13885 Add pass through opaque user data pointer to heap iterate
13886 functions and callbacks.
13887 In the CompiledMethodUnload event, send the code address.
13888 Add GarbageCollectionOccurred event.
13889 Add constant pool reference kind.
13890 Mark the functions CreateRawMonitor and DestroyRawMonitor
13891 as safe for use in heap callbacks and GC events.
13892 Clarify: VMDeath, GetCurrentThreadCpuTimerInfo,
13893 GetThreadCpuTimerInfo, IterateOverReachableObjects,
13894 IterateOverObjectsReachableFromObject, GetTime and
13895 JVMTI_ERROR_NULL_POINTER.
13896 Add missing errors to: GenerateEvents and
13897 AddToBootstrapClassLoaderSearch.
13898 Fix description of ClassFileLoadHook name parameter.
13899 In heap callbacks and GC/ObjectFree events, specify
13900 that only explicitly allowed functions can be called.
13901 Allow GetCurrentThreadCpuTimerInfo, GetCurrentThreadCpuTime,
13902 GetTimerInfo, and GetTime during callback.
13903 Allow calling SetTag/GetTag during the onload phase.
13904 SetEventNotificationMode, add: error attempted inappropriate
13905 thread level control.
13906 Remove jvmtiExceptionHandlerEntry.
13907 Fix handling of native methods on the stack --
13908 location_ptr param of GetFrameLocation, remove
13909 JVMTI_ERROR_OPAQUE_FRAME from GetFrameLocation,
13910 jvmtiFrameInfo.location, and jlocation.
13911 Remove typo (from JVMPI) implying that the MonitorWaited
13912 event is sent on sleep.
13913 </change>
13914 <change date="25 November 2003" version="0.2.94">
13915 Clarifications and typos.
13916 </change>
13917 <change date="3 December 2003" version="0.2.95">
13918 Allow NULL user_data in heap iterators.
13919 </change>
13920 <change date="28 January 2004" version="0.2.97">
13921 Add GetThreadState, deprecate GetThreadStatus.
13922 </change>
13923 <change date="29 January 2004" version="0.2.98">
13924 INVALID_SLOT and TYPE_MISMATCH errors should be optional.
13925 </change>
13926 <change date="12 February 2004" version="0.2.102">
13927 Remove MonitorContendedExit.
13928 Added JNIEnv parameter to VMObjectAlloc.
13929 Clarified definition of class_tag and referrer_index
13930 parameters to heap callbacks.
13931 </change>
13932 <change date="16 Febuary 2004" version="0.2.103">
13933 Document JAVA_TOOL_OPTIONS.
13934 </change>
13935 <change date="17 Febuary 2004" version="0.2.105">
13936 Divide start phase into primordial and start.
13937 Add VMStart event
13938 Change phase associations of functions and events.
13939 </change>
13940 <change date="18 Febuary 2004" version="0.3.6">
13941 Elide deprecated GetThreadStatus.
13942 Bump minor version, subtract 100 from micro version
13943 </change>
13944 <change date="18 Febuary 2004" version="0.3.7">
13945 Document that timer nanosecond values are unsigned.
13946 Clarify text having to do with native methods.
13947 </change>
13948 <change date="19 Febuary 2004" version="0.3.8">
13949 Fix typos.
13950 Remove elided deprecated GetThreadStatus.
13951 </change>
13952 <change date="23 Febuary 2004" version="0.3.9">
13953 Require NotifyFramePop to act on suspended threads.
13954 </change>
13955 <change date="24 Febuary 2004" version="0.3.10">
13956 Add capabilities
13957 (<internallink id="jvmtiCapabilities.can_redefine_any_class"
13958 ><code>can_redefine_any_class</code></internallink>
13959 and
13960 <internallink id="jvmtiCapabilities.can_generate_all_class_hook_events"
13961 ><code>can_generate_all_class_hook_events</code></internallink>)
13962 and an error (<errorlink id="JVMTI_ERROR_UNMODIFIABLE_CLASS"></errorlink>)
13963 which allow some classes to be unmodifiable.
13964 </change>
13965 <change date="28 Febuary 2004" version="0.3.11">
13966 Add JVMTI_ERROR_MUST_POSSESS_CAPABILITY to SetEventNotificationMode.
13967 </change>
13968 <change date="8 March 2004" version="0.3.12">
13969 Clarified CompiledMethodUnload so that it is clear the event
13970 may be posted after the class has been unloaded.
13971 </change>
13972 <change date="5 March 2004" version="0.3.13">
13973 Change the size parameter of VMObjectAlloc to jlong to match GetObjectSize.
13974 </change>
13975 <change date="13 March 2004" version="0.3.14">
13976 Added guideline for the use of the JNI FindClass function in event
13977 callback functions.
13978 </change>
13979 <change date="15 March 2004" version="0.3.15">
13980 Add GetAllStackTraces and GetThreadListStackTraces.
13981 </change>
13982 <change date="19 March 2004" version="0.3.16">
13983 ClassLoad and ClassPrepare events can be posted during start phase.
13984 </change>
13985 <change date="25 March 2004" version="0.3.17">
13986 Add JVMTI_ERROR_NATIVE_METHOD to GetLineNumberTable, GetLocalVariableTable,
13987 GetMaxLocals, GetArgumentsSize, GetMethodLocation, GetBytecodes.
13988 </change>
13989 <change date="29 March 2004" version="0.3.18">
13990 Return the timer kind in the timer information structure.
13991 </change>
13992 <change date="31 March 2004" version="0.3.19">
13993 Spec clarifications:
13994 JVMTI_THREAD_STATE_IN_NATIVE might not include JNI or <jvmti/>.
13995 ForceGarbageCollection does not run finalizers.
13996 The context of the specification is the Java platform.
13997 Warn about early instrumentation.
13998 </change>
13999 <change date="1 April 2004" version="0.3.20">
14000 Refinements to the above clarifications and
14001 Clarify that an error returned by Agent_OnLoad terminates the VM.
14002 </change>
14003 <change date="1 April 2004" version="0.3.21">
14004 Array class creation does not generate a class load event.
14005 </change>
14006 <change date="7 April 2004" version="0.3.22">
14007 Align thread state hierarchy more closely with java.lang.Thread.State.
14008 </change>
14009 <change date="12 April 2004" version="0.3.23">
14010 Clarify the documentation of thread state.
14011 </change>
14012 <change date="19 April 2004" version="0.3.24">
14013 Remove GarbageCollectionOccurred event -- can be done by agent.
14014 </change>
14015 <change date="22 April 2004" version="0.3.25">
14016 Define "command-line option".
14017 </change>
14018 <change date="29 April 2004" version="0.3.26">
14019 Describe the intended use of bytecode instrumentation.
14020 Fix description of extension event first parameter.
14021 </change>
14022 <change date="30 April 2004" version="0.3.27">
14023 Clarification and typos.
14024 </change>
14025 <change date="18 May 2004" version="0.3.28">
14026 Remove DataDumpRequest event.
14027 </change>
14028 <change date="18 May 2004" version="0.3.29">
14029 Clarify RawMonitorWait with zero timeout.
14030 Clarify thread state after RunAgentThread.
14031 </change>
14032 <change date="24 May 2004" version="0.3.30">
14033 Clean-up: fix bad/old links, etc.
14034 </change>
14035 <change date="30 May 2004" version="0.3.31">
14036 Clarifications including:
14037 All character strings are modified UTF-8.
14038 Agent thread visibiity.
14039 Meaning of obsolete method version.
14040 Thread invoking heap callbacks,
14041 </change>
14042 <change date="1 June 2004" version="1.0.32">
14043 Bump major.minor version numbers to "1.0".
14044 </change>
14045 <change date="2 June 2004" version="1.0.33">
14046 Clarify interaction between ForceGarbageCollection
14047 and ObjectFree.
14048 </change>
14049 <change date="6 June 2004" version="1.0.34">
14050 Restrict AddToBootstrapClassLoaderSearch and
14051 SetSystemProperty to the OnLoad phase only.
14052 </change>
14053 <change date="11 June 2004" version="1.0.35">
14054 Fix typo in SetTag.
14055 </change>
14056 <change date="18 June 2004" version="1.0.36">
14057 Fix trademarks.
14058 Add missing parameter in example GetThreadState usage.
14059 </change>
14060 <change date="4 August 2004" version="1.0.37">
14061 Copyright updates.
14062 </change>
14063 <change date="5 November 2004" version="1.0.38">
14064 Add missing function table layout.
14065 Add missing description of C++ member function format of functions.
14066 Clarify that name in CFLH can be NULL.
14067 Released as part of <tm>J2SE</tm> 5.0.
14068 </change>
14069 <change date="24 April 2005" version="1.1.47">
14070 Bump major.minor version numbers to "1.1".
14071 Add ForceEarlyReturn* functions.
14072 Add GetOwnedMonitorStackDepthInfo function.
14073 Add GetCurrentThread function.
14074 Add "since" version marker.
14075 Add AddToSystemClassLoaderSearch.
14076 Allow AddToBootstrapClassLoaderSearch be used in live phase.
14077 Fix historic rubbish in the descriptions of the heap_object_callback
14078 parameter of IterateOverHeap and IterateOverInstancesOfClass functions;
14079 disallow NULL for this parameter.
14080 Clarify, correct and make consistent: wording about current thread,
14081 opaque frames and insufficient number of frames in PopFrame.
14082 Consistently use "current frame" rather than "topmost".
14083 Clarify the JVMTI_ERROR_TYPE_MISMATCH errors in GetLocal* and SetLocal*
14084 by making them compatible with those in ForceEarlyReturn*.
14085 Many other clarifications and wording clean ups.
14086 </change>
14087 <change date="25 April 2005" version="1.1.48">
14088 Add GetConstantPool.
14089 Switch references to the first edition of the VM Spec, to the seconds edition.
14090 </change>
14091 <change date="26 April 2005" version="1.1.49">
14092 Clarify minor/major version order in GetConstantPool.
14093 </change>
14094 <change date="26 April 2005" version="1.1.50">
14095 Add SetNativeMethodPrefix and SetNativeMethodPrefixes.
14096 Reassign GetOwnedMonitorStackDepthInfo to position 153.
14097 Break out Class Loader Search in its own documentation category.
14098 Deal with overly long lines in XML source.
14099 </change>
14100 <change date="29 April 2005" version="1.1.51">
14101 Allow agents be started in the live phase.
14102 Added paragraph about deploying agents.
14103 </change>
14104 <change date="30 April 2005" version="1.1.52">
14105 Add specification description to SetNativeMethodPrefix(es).
14106 Better define the conditions on GetConstantPool.
14107 </change>
14108 <change date="30 April 2005" version="1.1.53">
14109 Break out the GetClassVersionNumber function from GetConstantPool.
14110 Clean-up the references to the VM Spec.
14111 </change>
14112 <change date="1 May 2005" version="1.1.54">
14113 Allow SetNativeMethodPrefix(es) in any phase.
14114 Add clarifications about the impact of redefinition on GetConstantPool.
14115 </change>
14116 <change date="2 May 2005" version="1.1.56">
14117 Various clarifications to SetNativeMethodPrefix(es).
14118 </change>
14119 <change date="2 May 2005" version="1.1.57">
14120 Add missing performance warning to the method entry event.
14121 </change>
14122 <change date="5 May 2005" version="1.1.58">
14123 Remove internal JVMDI support.
14124 </change>
14125 <change date="8 May 2005" version="1.1.59">
14126 Add <functionlink id="RetransformClasses"/>.
14127 Revamp the bytecode instrumentation documentation.
14128 Change <functionlink id="IsMethodObsolete"/> to no longer
14129 require the can_redefine_classes capability.
14130 </change>
14131 <change date="11 May 2005" version="1.1.63">
14132 Clarifications for retransformation.
14133 </change>
14134 <change date="11 May 2005" version="1.1.64">
14135 Clarifications for retransformation, per review.
14136 Lock "retransformation (in)capable" at class load enable time.
14137 </change>
14138 <change date="4 June 2005" version="1.1.67">
14139 Add new heap functionity which supports reporting primitive values,
14140 allows setting the referrer tag, and has more powerful filtering:
14141 FollowReferences, IterateThroughHeap, and their associated
14142 callbacks, structs, enums, and constants.
14143 </change>
14144 <change date="4 June 2005" version="1.1.68">
14145 Clarification.
14146 </change>
14147 <change date="6 June 2005" version="1.1.69">
14148 FollowReferences, IterateThroughHeap: Put callbacks in a struct;
14149 Add missing error codes; reduce bits in the visit control flags.
14150 </change>
14151 <change date="14 June 2005" version="1.1.70">
14152 More on new heap functionity: spec clean-up per review.
14153 </change>
14154 <change date="15 June 2005" version="1.1.71">
14155 More on new heap functionity: Rename old heap section to Heap (1.0).
14156 </change>
14157 <change date="21 June 2005" version="1.1.72">
14158 Fix typos.
14159 </change>
14160 <change date="27 June 2005" version="1.1.73">
14161 Make referrer info structure a union.
14162 </change>
14163 <change date="9 September 2005" version="1.1.74">
14164 In new heap functions:
14165 Add missing superclass reference kind.
14166 Use a single scheme for computing field indexes.
14167 Remove outdated references to struct based referrer info.
14168 </change>
14169 <change date="12 September 2005" version="1.1.75">
14170 Don't callback during FollowReferences on frivolous java.lang.Object superclass.
14171 </change>
14172 <change date="13 September 2005" version="1.1.76">
14173 In string primitive callback, length now Unicode length.
14174 In array and string primitive callbacks, value now "const".
14175 Note possible compiler impacts on setting JNI function table.
14176 </change>
14177 <change date="13 September 2005" version="1.1.77">
14178 GetClassVersionNumbers() and GetConstantPool() should return
14179 error on array or primitive class.
14180 </change>
14181 <change date="14 September 2005" version="1.1.78">
14182 Grammar fixes.
14183 </change>
14184 <change date="26 September 2005" version="1.1.79">
14185 Add IsModifiableClass query.
14186 </change>
14187 <change date="9 February 2006" version="1.1.81">
14188 Add referrer_class_tag parameter to jvmtiHeapReferenceCallback.
14189 </change>
14190 <change date="13 February 2006" version="1.1.82">
14191 Doc fixes: update can_redefine_any_class to include retransform.
14192 Clarify that exception events cover all Throwables.
14193 In GetStackTrace, no test is done for start_depth too big if start_depth is zero,
14194 Clarify fields reported in Primitive Field Callback -- static vs instance.
14195 Repair confusing names of heap types, including callback names.
14196 Require consistent usage of stack depth in the face of thread launch methods.
14197 Note incompatibility of <jvmti/> memory management with other systems.
14198 </change>
14199 <change date="14 February 2006" version="1.1.85">
14200 Fix typos and missing renames.
14201 </change>
14202 <change date="13 March 2006" version="1.1.86">
14203 Clarify that jmethodIDs and jfieldIDs can be saved.
14204 Clarify that Iterate Over Instances Of Class includes subclasses.
14205 </change>
14206 <change date="14 March 2006" version="1.1.87">
14207 Better phrasing.
14208 </change>
14209 <change date="16 March 2006" version="1.1.88">
14210 Match the referrer_index for static fields in Object Reference Callback
14211 with the Reference Implementation (and all other known implementations);
14212 that is, make it match the definition for instance fields.
14213 In GetThreadListStackTraces, add JVMTI_ERROR_INVALID_THREAD to cover
14214 an invalid thread in the list; and specify that not started threads
14215 return empty stacks.
14216 </change>
14217 <change date="17 March 2006" version="1.1.89">
14218 Typo.
14219 </change>
14220 <change date="25 March 2006" version="1.1.90">
14221 Typo.
14222 </change>
14223 <change date="6 April 2006" version="1.1.91">
14224 Remove restrictions on AddToBootstrapClassLoaderSearch and
14225 AddToSystemClassLoaderSearch.
14226 </change>
14227 <change date="1 May 2006" version="1.1.93">
14228 Changed spec to return -1 for monitor stack depth for the
14229 implementation which can not determine stack depth.
14230 </change>
14231 <change date="3 May 2006" version="1.1.94">
14232 Corrections for readability and accuracy courtesy of Alan Pratt of IBM.
14233 List the object relationships reported in FollowReferences.
14234 </change>
14235 <change date="5 May 2006" version="1.1.95">
14236 Clarify the object relationships reported in FollowReferences.
14237 </change>
14238 <change date="28 June 2006" version="1.1.98">
14239 Clarify DisposeEnvironment; add warning.
14240 Fix typos in SetLocalXXX "retrieve" => "set".
14241 Clarify that native method prefixes must remain set while used.
14242 Clarify that exactly one Agent_OnXXX is called per agent.
14243 Clarify that library loading is independent from start-up.
14244 Remove ambiguous reference to Agent_OnLoad in the Agent_OnUnload spec.
14245 </change>
14246 <change date="31 July 2006" version="1.1.99">
14247 Clarify the interaction between functions and exceptions.
14248 Clarify and give examples of field indices.
14249 Remove confusing "That is" sentence from MonitorWait and MonitorWaited events.
14250 Update links to point to Java 6.
14251 </change>
14252 <change date="6 August 2006" version="1.1.102">
14253 Add ResourceExhaustedEvent.
14254 </change>
14255 </changehistory>
14257 </specification>
14258 <!-- Keep this comment at the end of the file
14259 Local variables:
14260 mode: sgml
14261 sgml-omittag:t
14262 sgml-shorttag:t
14263 sgml-namecase-general:t
14264 sgml-general-insert-case:lower
14265 sgml-minimize-attributes:nil
14266 sgml-always-quote-attributes:t
14267 sgml-indent-step:2
14268 sgml-indent-data:t
14269 sgml-parent-document:nil
14270 sgml-exposed-tags:nil
14271 sgml-local-catalogs:nil
14272 sgml-local-ecat-files:nil
14273 End:
14274 -->