From 5b6355cb81d5404d359b14b6d8cb49a359831094 Mon Sep 17 00:00:00 2001
From: Pekka Enberg <penberg@kernel.org>
Date: Sun, 30 Oct 2011 07:36:38 +0000
Subject: Stefan Ring reports that commit f154af6 ("Fix HashMap.put() to check
 for hashCode equality before equals()") breaks running the CACAO test suite. 
 The breakage looks like this:

  LD_LIBRARY_PATH=../../../src/cacao/.libs ../../../src/cacao/cacao -Xbootclasspath:../../../src/classes/classes:/home/sr/classpathcvs/share/classpath/glibj.zip -classpath /usr/share/java/junit4.jar:. org.junit.runner.JUnitCore All
  JUnit version 4.5
  .E
  Time: 0.003
  There was 1 failure:
  1) initializationError(All)
  java.lang.NullPointerException
     at java.util.HashMap.put(HashMap.java:348)
     at java.util.HashSet.add(HashSet.java:151)
     at org.junit.runners.model.RunnerBuilder.addParent(RunnerBuilder.java:64)
     at org.junit.runners.model.RunnerBuilder.runners(RunnerBuilder.java:81)
     at org.junit.runners.Suite.<init>(Suite.java:88)
     at org.junit.runners.Suite.<init>(Suite.java:54)
     at java.lang.reflect.VMConstructor.construct(Native Method)
     at java.lang.reflect.Constructor.newInstance(Constructor.java:318)
     at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:35)
     at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:24)
     at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:57)
     at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:29)
     at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:57)
     at org.junit.runners.model.RunnerBuilder.runners(RunnerBuilder.java:93)
     at org.junit.runners.model.RunnerBuilder.runners(RunnerBuilder.java:84)
     at org.junit.runners.Suite.<init>(Suite.java:66)
     at org.junit.runner.Request.classes(Request.java:68)
     at org.junit.runner.JUnitCore.run(JUnitCore.java:107)
     at org.junit.runner.JUnitCore.runMain(JUnitCore.java:88)
     at org.junit.runner.JUnitCore.runMainAndExit(JUnitCore.java:54)
     at org.junit.runner.JUnitCore.main(JUnitCore.java:46)

  FAILURES!!!
  Tests run: 1,  Failures: 1

Looking at the code, it's obviously broken for HashMap.put() with a null key.

2011-10-24  Pekka Enberg  <penberg@kernel.org>

        * java/util/HashMap.java:
        (put): Fix NullPointerException for null keys.
---
 java/util/HashMap.java | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'java')

diff --git a/java/util/HashMap.java b/java/util/HashMap.java
index 9d64fecb4..f5194a240 100644
--- a/java/util/HashMap.java
+++ b/java/util/HashMap.java
@@ -343,9 +343,12 @@ public class HashMap<K, V> extends AbstractMap<K, V>
     int idx = hash(key);
     HashEntry<K, V> e = buckets[idx];
 
+    int hash1 = key == null ? 0 : key.hashCode();
     while (e != null)
       {
-        if ((key.hashCode() == e.key.hashCode()) && equals(key, e.key))
+        int hash2 = e.key == null ? 0 : e.key.hashCode();
+
+        if ((hash1 == hash2) && equals(key, e.key))
           {
             e.access(); // Must call this for bookkeeping in LinkedHashMap.
             V r = e.value;
-- 
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