/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import java.lang.ref.WeakReference;
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public class Main {
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static final int numWeakReferences = 16 * 1024;
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static WeakReference[] weakReferences = new WeakReference[numWeakReferences];
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static volatile boolean done = false;
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static Object keepAlive;
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public static void main(String[] args) throws Exception {
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// Try to call Reference.get repeatedly while the GC is running.
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Thread gcThread = new GcThread();
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Thread[] readerThread = new ReaderThread[4];
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for (int i = 0; i < readerThread.length; ++i) {
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readerThread[i] = new ReaderThread();
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}
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gcThread.start();
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for (int i = 0; i < readerThread.length; ++i) {
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readerThread[i].start();
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}
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gcThread.join();
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for (int i = 0; i < readerThread.length; ++i) {
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readerThread[i].join();
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}
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System.out.println("PASS");
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}
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static class GcThread extends Thread {
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GcThread() {
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Object temp = new Object();
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for (int j = 0; j < weakReferences.length; ++j) {
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weakReferences[j] = new WeakReference(temp);
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}
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}
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public void run() {
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for (int i = 0; i < 1000; ++i) {
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Object o = new Object();
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for (int j = 0; j < weakReferences.length; ++j) {
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weakReferences[j] = new WeakReference(o);
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}
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}
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done = true;
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}
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}
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static class ReaderThread extends Thread {
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public void run() {
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while (!done) {
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for (int j = 0; j < weakReferences.length; ++j) {
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keepAlive = weakReferences[j].get();
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}
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for (int j = 0; j < weakReferences.length; ++j) {
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weakReferences[j].clear();
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}
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}
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}
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}
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}
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