| /* |
| * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /** |
| * @test |
| * @bug 8046085 |
| * @summary Ensure that when trees are being used for collisions that null key |
| * insertion still works. |
| */ |
| |
| import java.util.*; |
| import java.util.stream.IntStream; |
| |
| public class PutNullKey { |
| |
| // Initial capacity of map |
| // Should be >= the map capacity for treeifying, see HashMap/ConcurrentMap.MIN_TREEIFY_CAPACITY |
| static final int INITIAL_CAPACITY = 64; |
| |
| // Maximum size of map |
| // Should be > the treeify threshold, see HashMap/ConcurrentMap.TREEIFY_THRESHOLD |
| static final int SIZE = 256; |
| |
| // Load factor of map |
| // A value 1.0 will ensure that a new threshold == capacity |
| static final float LOAD_FACTOR = 1.0f; |
| |
| public static class CollidingHash implements Comparable<CollidingHash> { |
| |
| private final int value; |
| |
| public CollidingHash(int value) { |
| this.value = value; |
| } |
| |
| @Override |
| public int hashCode() { |
| // intentionally bad hashcode. Force into first bin. |
| return 0; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (null == o) { |
| return false; |
| } |
| |
| if (o.getClass() != CollidingHash.class) { |
| return false; |
| } |
| |
| return value == ((CollidingHash) o).value; |
| } |
| |
| @Override |
| public int compareTo(CollidingHash o) { |
| return value - o.value; |
| } |
| } |
| |
| public static void main(String[] args) throws Exception { |
| Map<Object,Object> m = new HashMap<>(INITIAL_CAPACITY, LOAD_FACTOR); |
| IntStream.range(0, SIZE) |
| .mapToObj(CollidingHash::new) |
| .forEach(e -> { m.put(e, e); }); |
| |
| // kaboom? |
| m.put(null, null); |
| } |
| } |