82 lines
2.8 KiB
Java
82 lines
2.8 KiB
Java
/*
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* Copyright (c) 2013, 2022, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* @test KeepAliveClass
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* @summary This test case uses a java.lang.Class instance to keep a class alive.
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* @requires vm.opt.final.ClassUnloading
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* @modules java.base/jdk.internal.misc
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* @library /test/lib
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* @library classes
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* @build jdk.test.whitebox.WhiteBox test.Empty
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* @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
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* @run main/othervm -Xbootclasspath/a:. -Xmn8m -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI KeepAliveClass
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*/
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import java.lang.ref.SoftReference;
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import jdk.test.whitebox.WhiteBox;
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import jdk.test.lib.classloader.ClassUnloadCommon;
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/**
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* Test that verifies that classes are not unloaded when specific types of references are kept to them.
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*/
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public class KeepAliveClass {
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private static final String className = "test.Empty";
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private static final WhiteBox wb = WhiteBox.getWhiteBox();
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public static Object escape = null;
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public static void main(String... args) throws Exception {
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ClassLoader cl = ClassUnloadCommon.newClassLoader();
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Class<?> c = cl.loadClass(className);
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Object o = c.newInstance();
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o = null; cl = null;
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escape = c;
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{
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boolean isAlive = wb.isClassAlive(className);
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System.out.println("testClass (1) alive: " + isAlive);
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ClassUnloadCommon.failIf(!isAlive, "should be alive");
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}
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ClassUnloadCommon.triggerUnloading();
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{
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boolean isAlive = wb.isClassAlive(className);
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System.out.println("testClass (2) alive: " + isAlive);
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ClassUnloadCommon.failIf(!isAlive, "should be alive");
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}
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c = null;
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escape = null;
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ClassUnloadCommon.triggerUnloading();
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{
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boolean isAlive = wb.isClassAlive(className);
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System.out.println("testClass (3) alive: " + isAlive);
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ClassUnloadCommon.failIf(isAlive, "should be unloaded");
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}
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}
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}
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