1/* 2 * Copyright (c) 2013, 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 * Portions Copyright (c) 2013 IBM Corporation 26 */ 27 28/** 29 * @test 30 * @bug 8019381 31 * @summary Verify that we do not get exception when we override isEmpty() 32 * in a subclass of HashMap 33 * @author zhangshj@linux.vnet.ibm.com 34 */ 35 36import java.util.function.BiFunction; 37import java.util.HashMap; 38 39public class OverrideIsEmpty { 40 public static class NotEmptyHashMap<K,V> extends HashMap<K,V> { 41 private K alwaysExistingKey; 42 private V alwaysExistingValue; 43 44 @Override 45 public V get(Object key) { 46 if (key == alwaysExistingKey) { 47 return alwaysExistingValue; 48 } 49 return super.get(key); 50 } 51 52 @Override 53 public int size() { 54 return super.size() + 1; 55 } 56 57 @Override 58 public boolean isEmpty() { 59 return size() == 0; 60 } 61 } 62 63 public static void main(String[] args) { 64 NotEmptyHashMap<Object, Object> map = new NotEmptyHashMap<>(); 65 Object key = new Object(); 66 Object value = new Object(); 67 map.get(key); 68 map.remove(key); 69 map.replace(key, value, null); 70 map.replace(key, value); 71 map.computeIfPresent(key, new BiFunction<Object, Object, Object>() { 72 public Object apply(Object key, Object oldValue) { 73 return oldValue; 74 } 75 }); 76 } 77} 78 79