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/*
* 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);
}
}
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