84 lines
2.9 KiB
Java
84 lines
2.9 KiB
Java
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/*
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* Copyright (c) 2021, 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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import java.lang.ref.Reference;
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import java.lang.ref.WeakReference;
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import java.io.ObjectStreamClass;
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import java.io.Serializable;
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import java.util.ArrayList;
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import org.testng.annotations.Test;
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import static org.testng.Assert.assertFalse;
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import static org.testng.Assert.assertTrue;
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/* @test
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* @bug 8277072
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* @library /test/lib/
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* @summary ObjectStreamClass caches keep ClassLoaders alive
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* @run testng/othervm -Xmx10m -XX:SoftRefLRUPolicyMSPerMB=1 ObjectStreamClassCaching
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*/
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public class ObjectStreamClassCaching {
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@Test
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public void testCachingEffectiveness() throws Exception {
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var ref = lookupObjectStreamClass(TestClass.class);
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System.gc();
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Thread.sleep(100L);
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// to trigger any ReferenceQueue processing...
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lookupObjectStreamClass(AnotherTestClass.class);
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assertFalse(ref.refersTo(null),
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"Cache lost entry although memory was not under pressure");
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}
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@Test
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public void testCacheReleaseUnderMemoryPressure() throws Exception {
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var ref = lookupObjectStreamClass(TestClass.class);
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pressMemoryHard(ref);
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System.gc();
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Thread.sleep(100L);
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assertTrue(ref.refersTo(null),
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"Cache still has entry although memory was pressed hard");
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}
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// separate method so that the looked-up ObjectStreamClass is not kept on stack
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private static WeakReference<?> lookupObjectStreamClass(Class<?> cl) {
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return new WeakReference<>(ObjectStreamClass.lookup(cl));
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}
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private static void pressMemoryHard(Reference<?> ref) {
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try {
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var list = new ArrayList<>();
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while (!ref.refersTo(null)) {
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list.add(new byte[1024 * 1024 * 64]); // 64 MiB chunks
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}
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} catch (OutOfMemoryError e) {
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// release
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}
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}
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}
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class TestClass implements Serializable {
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}
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class AnotherTestClass implements Serializable {
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}
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