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 36 package test.java.util.HashMap; 37 38 import java.util.function.BiFunction; 39 import java.util.HashMap; 40 41 public class OverrideIsEmpty { 42 public static class NotEmptyHashMap<K,V> extends HashMap<K,V> { 43 private K alwaysExistingKey; 44 private V alwaysExistingValue; 45 46 @Override get(Object key)47 public V get(Object key) { 48 if (key == alwaysExistingKey) { 49 return alwaysExistingValue; 50 } 51 return super.get(key); 52 } 53 54 @Override size()55 public int size() { 56 return super.size() + 1; 57 } 58 59 @Override isEmpty()60 public boolean isEmpty() { 61 return size() == 0; 62 } 63 } 64 main(String[] args)65 public static void main(String[] args) { 66 NotEmptyHashMap<Object, Object> map = new NotEmptyHashMap<>(); 67 Object key = new Object(); 68 Object value = new Object(); 69 map.get(key); 70 map.remove(key); 71 map.replace(key, value, null); 72 map.replace(key, value); 73 map.computeIfPresent(key, new BiFunction<Object, Object, Object>() { 74 public Object apply(Object key, Object oldValue) { 75 return oldValue; 76 } 77 }); 78 } 79 } 80 81