1 /* 2 * Copyright (c) 2000, 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 4332184 26 * @summary Ensure that ObjectOutputStream properly releases strong references 27 * to written objects when reset() is called. 28 */ 29 30 import java.io.*; 31 import java.lang.ref.WeakReference; 32 import java.util.ArrayList; 33 import java.util.Iterator; 34 import java.util.List; 35 36 public class ClearHandleTable { 37 private static final int TIMES = 1000; 38 39 public static void main(String[] args) throws Exception { 40 final int nreps = 100; 41 ObjectOutputStream oout = 42 new ObjectOutputStream(new ByteArrayOutputStream()); 43 List<WeakReference<?>> refs = new ArrayList<>(nreps); 44 45 for (int i = 0; i < nreps; i++) { 46 String str = new String("blargh"); 47 oout.writeObject(str); 48 refs.add(new WeakReference<Object>(str)); 49 } 50 51 oout.reset(); 52 53 int count = 0; 54 for (int i=0; i<TIMES; i++) { 55 // relying on, possibly multiple, System.gc calls to clear weak references 56 System.gc(); 57 58 Iterator<WeakReference<?>> itr = refs.iterator(); 59 while(itr.hasNext()) { 60 WeakReference<?> ref = itr.next(); 61 if (ref.get() == null) { 62 itr.remove(); 63 } 64 } 65 if (refs.isEmpty()) 66 break; 67 Thread.sleep(20); 68 count++; 69 if (count % 10 == 0) 70 System.out.println("Looping " + count + " times"); 71 } 72 73 if (!refs.isEmpty()) { 74 throw new Error("failed to garbage collect object"); 75 } 76 } 77 } --- EOF ---