Specification

http://download.java.net/jdk8/docs/api/java/util/Map.html#merge%28K,%20V,%20java.util.function.BiFunction%29

states:

"If the specified key is not already associated with a value or is associated with null, associates it with the given value."

The implementation behavior of JDK8-LAMBDA (probably starting from b106) contradicts the spec in case if the given key is associated with "null"

Consider the following code sample:

-------------------------------
        final HashMap map = new HashMap();
        map.put("a", null);
        System.out.println("result = " + map.merge("a", "new", (v1, v2) -> "merged"));
-------------------------------

JDK8b106-lambda:

result = merged

on JDK8b106:

result = new


The following JCK tests fail due to this:
api/java_util/Collections/checked/CheckedMap8Tests.html#CheckedMap8Tests[merge_nullKeyValue_noNPE]
api/java_util/Collections/checked/CheckedMap8Tests.html#CheckedMap8Tests[merge_nullKey_noNPE]
api/java_util/Collections/synchronizd/SynchronizedMap8Tests.html#SynchronizedMap8Tests[merge_nullKeyValue_noNPE]
api/java_util/Collections/synchronizd/SynchronizedMap8Tests.html#SynchronizedMap8Tests[merge_nullKey_noNPE]
api/java_util/HashMap/Map8Tests.html#Map8Tests[merge_nullKeyValue_noNPE]
api/java_util/HashMap/Map8Tests.html#Map8Tests[merge_nullKey_noNPE]
api/java_util/LinkedHashMap/Map8Tests.html#Map8Tests[merge_nullKeyValue_noNPE]
api/java_util/LinkedHashMap/Map8Tests.html#Map8Tests[merge_nullKey_noNPE]
api/java_util/Collections/checked/CheckedMap8Tests.html#CheckedMap8Tests[merge_presentKey_mappedToNull_newValue]
api/java_util/Collections/synchronizd/SynchronizedMap8Tests.html#SynchronizedMap8Tests[merge_presentKey_mappedToNull_newValue]
api/java_util/HashMap/Map8Tests.html#Map8Tests[merge_presentKey_mappedToNull_newValue]
api/java_util/LinkedHashMap/Map8Tests.html#Map8Tests[merge_presentKey_mappedToNull_newValue]