4245470: algorithm of java.lang.Byte.hashCode() is not specified
Summary: Specify some hashCode methods are equivalent to intValue
Reviewed-by: darcy
--- a/jdk/src/share/classes/java/lang/Byte.java Tue Sep 22 16:11:23 2009 -0700
+++ b/jdk/src/share/classes/java/lang/Byte.java Tue Sep 22 18:30:58 2009 -0700
@@ -378,7 +378,10 @@
}
/**
- * Returns a hash code for this {@code Byte}.
+ * Returns a hash code for this {@code Byte}; equal to the result
+ * of invoking {@code intValue()}.
+ *
+ * @return a hash code value for this {@code Byte}
*/
public int hashCode() {
return (int)value;
--- a/jdk/src/share/classes/java/lang/Character.java Tue Sep 22 16:11:23 2009 -0700
+++ b/jdk/src/share/classes/java/lang/Character.java Tue Sep 22 18:30:58 2009 -0700
@@ -2612,8 +2612,10 @@
}
/**
- * Returns a hash code for this <code>Character</code>.
- * @return a hash code value for this object.
+ * Returns a hash code for this {@code Character}; equal to the result
+ * of invoking {@code charValue()}.
+ *
+ * @return a hash code value for this {@code Character}
*/
public int hashCode() {
return (int)value;
--- a/jdk/src/share/classes/java/lang/Short.java Tue Sep 22 16:11:23 2009 -0700
+++ b/jdk/src/share/classes/java/lang/Short.java Tue Sep 22 18:30:58 2009 -0700
@@ -383,7 +383,10 @@
}
/**
- * Returns a hash code for this {@code Short}.
+ * Returns a hash code for this {@code Short}; equal to the result
+ * of invoking {@code intValue()}.
+ *
+ * @return a hash code value for this {@code Short}
*/
public int hashCode() {
return (int)value;
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/lang/HashCode.java Tue Sep 22 18:30:58 2009 -0700
@@ -0,0 +1,80 @@
+/*
+ * Copyright 2009 Google, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ * @test
+ * @bug 4245470
+ * @summary Test the primitive wrappers hashCode()
+ */
+
+import java.util.Random;
+
+public class HashCode {
+
+ final Random rnd = new Random();
+
+ void test(String args[]) throws Exception {
+ int[] ints = {
+ Integer.MIN_VALUE,
+ Short.MIN_VALUE,
+ Character.MIN_VALUE,
+ Byte.MIN_VALUE,
+ -1, 0, 1,
+ Byte.MAX_VALUE,
+ Character.MAX_VALUE,
+ Short.MAX_VALUE,
+ Integer.MAX_VALUE,
+ rnd.nextInt(),
+ };
+
+ for (int x : ints) {
+ check( new Long(x).hashCode() == (int)((long)x ^ (long)x>>>32));
+ check(Long.valueOf(x).hashCode() == (int)((long)x ^ (long)x>>>32));
+ check( new Integer(x).hashCode() == x);
+ check(Integer.valueOf(x).hashCode() == x);
+ check( new Short((short)x).hashCode() == (short) x);
+ check(Short.valueOf((short)x).hashCode() == (short) x);
+ check( new Character((char) x).hashCode() == (char) x);
+ check(Character.valueOf((char) x).hashCode() == (char) x);
+ check( new Byte((byte) x).hashCode() == (byte) x);
+ check(Byte.valueOf((byte) x).hashCode() == (byte) x);
+ }
+ }
+
+ //--------------------- Infrastructure ---------------------------
+ volatile int passed = 0, failed = 0;
+ void pass() {passed++;}
+ void fail() {failed++; Thread.dumpStack();}
+ void fail(String msg) {System.err.println(msg); fail();}
+ void unexpected(Throwable t) {failed++; t.printStackTrace();}
+ void check(boolean cond) {if (cond) pass(); else fail();}
+ void equal(Object x, Object y) {
+ if (x == null ? y == null : x.equals(y)) pass();
+ else fail(x + " not equal to " + y);}
+ public static void main(String[] args) throws Throwable {
+ new HashCode().instanceMain(args);}
+ public void instanceMain(String[] args) throws Throwable {
+ try {test(args);} catch (Throwable t) {unexpected(t);}
+ System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
+ if (failed > 0) throw new AssertionError("Some tests failed");}
+}