@Override
    public int hashCode() {
      int h = 0;
      for (Entry<Key<K>,V> entry : hashEntrySet) {
        Key<K> wk = entry.getKey();
        if (wk == null) continue;
        Object v;
        h += wk.hashCode() ^ ((v = entry.getValue()) == null ? 0 : v.hashCode());
      }
      return h;
    }
@Override
    public int hashCode()