protected boolean equalityCompareWithNulls(final Object key, final Object mapKey) {
      if (key != mapKey) {
        if (key != null) {
          return key.equals(mapKey);
        }
        return false;
      }
      return true;
    }
Added for GemFire since it stores some keys inline.
geode-core/src/main/java/org/apache/geode/internal/util/concurrent/CustomEntryConcurrentHashMap.java