100 lines
3.5 KiB
Java
100 lines
3.5 KiB
Java
/*
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* Copyright (c) 2017, 2020, 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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import java.lang.instrument.ClassFileTransformer;
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import java.lang.instrument.Instrumentation;
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import java.lang.instrument.IllegalClassFormatException;
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import java.lang.ref.Cleaner;
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import java.security.ProtectionDomain;
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public class GCDuringDumpTransformer implements ClassFileTransformer {
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static boolean TEST_WITH_CLEANER = Boolean.getBoolean("test.with.cleaner");
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static Cleaner cleaner;
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static Thread thread;
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static Object garbage;
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static {
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if (TEST_WITH_CLEANER) {
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cleaner = Cleaner.create();
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garbage = new Object();
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cleaner.register(garbage, new MyCleaner());
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System.out.println("Registered cleaner");
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}
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}
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public byte[] transform(ClassLoader loader, String name, Class<?> classBeingRedefined,
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ProtectionDomain pd, byte[] buffer) throws IllegalClassFormatException {
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if (TEST_WITH_CLEANER) {
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if (name.equals("Hello")) {
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garbage = null;
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System.out.println("Unreferenced GCDuringDumpTransformer.garbage");
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}
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} else {
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try {
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makeGarbage();
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} catch (Throwable t) {
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t.printStackTrace();
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try {
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Thread.sleep(200); // let GC to have a chance to run
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} catch (Throwable t2) {}
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}
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}
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return null;
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}
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private static Instrumentation savedInstrumentation;
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public static void premain(String agentArguments, Instrumentation instrumentation) {
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System.out.println("ClassFileTransformer.premain() is called: TEST_WITH_CLEANER = " + TEST_WITH_CLEANER);
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instrumentation.addTransformer(new GCDuringDumpTransformer(), /*canRetransform=*/true);
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savedInstrumentation = instrumentation;
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}
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public static Instrumentation getInstrumentation() {
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return savedInstrumentation;
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}
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public static void agentmain(String args, Instrumentation inst) throws Exception {
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premain(args, inst);
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}
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public static void makeGarbage() {
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for (int x=0; x<10; x++) {
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Object[] a = new Object[10000];
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}
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}
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static class MyCleaner implements Runnable {
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static int count = 0;
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int i = count++;
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public void run() {
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// Allocate something. This will cause G1 to allocate an EDEN region.
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// See JDK-8245925
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Object o = new Object();
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System.out.println("cleaning " + i);
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}
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}
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}
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