1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/test/runtime/ClassUnload/KeepAliveSoftReference.java Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,80 @@
1.4 +/*
1.5 + * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + */
1.26 +
1.27 +/*
1.28 + * @test KeepAliveSoftReference
1.29 + * @summary This test case uses a java.lang.ref.SoftReference referencing a class instance to keep a class alive.
1.30 + * @library /testlibrary /testlibrary/whitebox /runtime/testlibrary
1.31 + * @library classes
1.32 + * @build KeepAliveSoftReference test.Empty
1.33 + * @build ClassUnloadCommon
1.34 + * @run main ClassFileInstaller sun.hotspot.WhiteBox
1.35 + * @run main/othervm -Xbootclasspath/a:. -Xmn8m -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI KeepAliveSoftReference
1.36 + */
1.37 +
1.38 +import java.lang.ref.SoftReference;
1.39 +import sun.hotspot.WhiteBox;
1.40 +
1.41 +/**
1.42 + * Test that verifies that classes are not unloaded when specific types of references are kept to them.
1.43 + */
1.44 +public class KeepAliveSoftReference {
1.45 + private static final String className = "test.Empty";
1.46 + private static final WhiteBox wb = WhiteBox.getWhiteBox();
1.47 +
1.48 + public static void main(String... args) throws Exception {
1.49 + ClassLoader cl = ClassUnloadCommon.newClassLoader();
1.50 + Class<?> c = cl.loadClass(className);
1.51 + Object o = c.newInstance();
1.52 + SoftReference<Object> sr = new SoftReference(o);
1.53 + o = null; c = null; cl = null;
1.54 +
1.55 + {
1.56 + boolean isAlive = wb.isClassAlive(className);
1.57 + System.out.println("testSoftReference (1) alive: " + isAlive);
1.58 + boolean cleared = (sr.get() == null);
1.59 + boolean shouldBeAlive = !cleared;
1.60 + ClassUnloadCommon.failIf(isAlive != shouldBeAlive, "" + isAlive + " != " + shouldBeAlive);
1.61 + }
1.62 +
1.63 + ClassUnloadCommon.triggerUnloading();
1.64 +
1.65 + {
1.66 + boolean isAlive = wb.isClassAlive(className);
1.67 + System.out.println("testSoftReference (2) alive: " + isAlive);
1.68 + boolean cleared = (sr.get() == null);
1.69 + boolean shouldBeAlive = !cleared;
1.70 + ClassUnloadCommon.failIf(isAlive != shouldBeAlive, "" + isAlive + " != " + shouldBeAlive);
1.71 + }
1.72 + sr.clear();
1.73 + ClassUnloadCommon.triggerUnloading();
1.74 +
1.75 + {
1.76 + boolean isAlive = wb.isClassAlive(className);
1.77 + System.out.println("testSoftReference (3) alive: " + isAlive);
1.78 + boolean cleared = (sr.get() == null);
1.79 + boolean shouldBeAlive = !cleared;
1.80 + ClassUnloadCommon.failIf(isAlive != shouldBeAlive, "" + isAlive + " != " + shouldBeAlive);
1.81 + }
1.82 + }
1.83 +}
