1 /* 2 * Copyright (c) 2013, 2018, 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 /** 25 * @test 26 * @bug 7042126 27 * @summary Verify that we do not leak contents when we clone a HashMap 28 * @author david.buck@oracle.com 29 * @run main/othervm HashMapCloneLeak 30 * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+EliminateAutoBox -XX:AutoBoxCacheMax=20000 HashMapCloneLeak 31 */ 32 33 import java.util.HashMap; 34 import java.lang.ref.WeakReference; 35 36 public class HashMapCloneLeak { 37 38 static WeakReference<Object> wr = null; 39 40 // helper method to keep testObject and map out of main method's scope 41 private static HashMap<Integer, Object> makeMap() { 42 HashMap<Integer, Object> map = new HashMap<Integer, Object>(); 43 Object testObject = new Object(); 44 wr = new WeakReference<Object>(testObject); 45 map.put(42, testObject); 46 return map; 47 } 48 49 public static void main(String[] args) throws Exception { 50 HashMap<Integer, Object> hm = makeMap(); 51 hm = (HashMap<Integer, Object>)hm.clone(); 52 hm.clear(); 53 // There should no longer be a strong reference to testObject 54 // the WeakReference should be nulled out by GC. If not, 55 // we will hang here until timed out by the test harness. 56 Object[] chain = null; 57 while (wr.get() != null) { 58 try { 59 Object[] allocate = new Object[1000000]; 60 allocate[0] = chain; 61 chain = allocate; 62 } catch (OutOfMemoryError oome) { 63 chain = null; 64 } 65 System.gc(); 66 Thread.sleep(100); 67 } 68 } 69 70 }