--- old/src/share/classes/java/util/HashMap.java 2014-06-06 12:46:36.884269031 -0700 +++ new/src/share/classes/java/util/HashMap.java 2014-06-06 12:46:36.688269021 -0700 @@ -1967,7 +1967,7 @@ dir = -1; else if (ph < h) dir = 1; - else if ((pk = p.key) == k || (pk != null && k.equals(pk))) + else if ((pk = p.key) == k || (k != null && k.equals(pk))) return p; else if ((kc == null && (kc = comparableClassFor(k)) == null) || --- /dev/null 2014-06-02 09:24:57.809038016 -0700 +++ new/test/java/util/HashMap/PutNullKey.java 2014-06-06 12:46:37.564269064 -0700 @@ -0,0 +1,90 @@ +/* + * 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 treeifiying, 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 { + + 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 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); + } +}