Tue, 08 Aug 2017 15:57:29 +0800
merge
1 /*
2 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 import java.security.*;
24 import java.lang.instrument.*;
25 import java.lang.reflect.*;
27 public class Agent implements ClassFileTransformer {
28 public synchronized byte[] transform(final ClassLoader classLoader,
29 final String className,
30 Class<?> classBeingRedefined,
31 ProtectionDomain protectionDomain,
32 byte[] classfileBuffer) {
33 System.out.println("Transforming class " + className);
34 return classfileBuffer;
35 }
37 public static void redefine(String agentArgs, Instrumentation instrumentation, Class to_redefine) {
39 try {
40 instrumentation.retransformClasses(to_redefine);
41 } catch (Exception e) {
42 e.printStackTrace();
43 }
45 }
47 public static void premain(String agentArgs, Instrumentation instrumentation) {
48 Agent transformer = new Agent();
49 instrumentation.addTransformer(transformer, true);
51 // Redefine java/lang/Object and java/lang/reflect/Method.invoke and
52 // java/lang/ClassLoader
53 Class object_class = Object.class;
54 redefine(agentArgs, instrumentation, object_class);
56 Class method_class = Method.class;
57 redefine(agentArgs, instrumentation, method_class);
59 Class loader_class = ClassLoader.class;
60 redefine(agentArgs, instrumentation, loader_class);
62 instrumentation.removeTransformer(transformer);
63 }
65 public static void main(String[] args) {
66 byte[] ba = new byte[0];
68 // If it survives 1000 GC's, it's good.
69 for (int i = 0; i < 1000 ; i++) {
70 System.gc();
71 ba.clone();
72 }
73 try {
74 // Use java/lang/reflect/Method.invoke to call
75 WalkThroughInvoke a = new WalkThroughInvoke();
76 Class aclass = WalkThroughInvoke.class;
77 Method m = aclass.getMethod("stackWalk");
78 m.invoke(a);
79 } catch (Exception x) {
80 x.printStackTrace();
81 }
82 }
83 }