guava/src/com/google/common/collect/ForwardingMapEntry.java
protected int standardHashCode() {
    K k = getKey();
    V v = getValue();
    return ((k == null) ? 0 : k.hashCode()) ^ ((v == null) ? 0 : v.hashCode());
  }
protected int standardHashCode() {
    K k = getKey();
    V v = getValue();
    return ((k == null) ? 0 : k.hashCode()) ^ ((v == null) ? 0 : v.hashCode());
  }
A sensible definition of {@link #hashCode()} in terms of {@link #getKey()} and {@link
#getValue()}. If you override either of these methods, you may wish to override {@link
#hashCode()} to forward to this implementation.

@since 7.0