1 /* 2 * Copyright (c) 2011, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* @test 25 * @bug 4268317 8132306 8175797 26 * @summary Test if Reference.enqueue() works properly with GC 27 * @run main ReferenceEnqueue 28 */ 29 30 import java.lang.ref.*; 31 import java.util.ArrayList; 32 import java.util.List; 33 34 public class ReferenceEnqueue { 35 36 public static void main(String args[]) throws Exception { 37 for (int i=0; i < 5; i++) { 38 new WeakRef().run(); 39 new ExplicitEnqueue().run(); 40 } 41 System.out.println("Test passed."); 42 } 43 44 static class WeakRef { 45 final ReferenceQueue<Object> queue = new ReferenceQueue<Object>(); 46 final Reference<Object> ref; 47 final int iterations = 1000; 48 49 WeakRef() { 50 this.ref = new WeakReference<Object>(new Object(), queue); 51 } 52 53 void run() throws InterruptedException { 54 System.gc(); 55 for (int i = 0; i < iterations; i++) { 56 System.gc(); 57 if (ref.isEnqueued()) { 58 break; 59 } 60 61 Thread.sleep(100); 62 } 63 64 if (ref.isEnqueued() == false) { 65 // GC have not enqueued refWeak for the timeout period 66 System.out.println("Reference not enqueued yet"); 67 return; 68 } 69 70 if (ref.enqueue() == true) { 71 // enqueue() should return false since 72 // ref is already enqueued by the GC 73 throw new RuntimeException("Error: enqueue() returned true;" 74 + " expected false"); 75 } 76 77 if (queue.poll() == null) { 78 // poll() should return ref enqueued by the GC 79 throw new RuntimeException("Error: poll() returned null;" 80 + " expected ref object"); 81 } 82 } 83 } 84 85 static class ExplicitEnqueue { 86 final ReferenceQueue<Object> queue = new ReferenceQueue<>(); 87 final List<Reference<Object>> refs = new ArrayList<>(); 88 final int iterations = 1000; 89 90 ExplicitEnqueue() { 91 this.refs.add(new SoftReference<>(new Object(), queue)); 92 this.refs.add(new WeakReference<>(new Object(), queue)); 93 // Can't test PhantomReference because get() always returns null. 94 } 95 96 void run() throws InterruptedException { 97 for (Reference<Object> ref : refs) { 98 if (ref.enqueue() == false) { 99 throw new RuntimeException("Error: enqueue failed"); 100 } 101 if (ref.get() != null) { 102 throw new RuntimeException("Error: referent must be cleared"); 103 } 104 } 105 106 System.gc(); 107 for (int i = 0; refs.size() > 0 && i < iterations; i++) { 108 Reference<Object> ref = (Reference<Object>)queue.poll(); 109 if (ref == null) { 110 System.gc(); 111 Thread.sleep(100); 112 continue; 113 } 114 115 if (refs.remove(ref) == false) { 116 throw new RuntimeException("Error: unknown reference " + ref); 117 } 118 } 119 120 if (!refs.isEmpty()) { 121 throw new RuntimeException("Error: not all references are removed"); 122 } 123 } 124 } 125 }