public ObjectSortedSet<Reference2CharMap.Entry<K>> reference2CharEntrySet() {
   if (entries == null)
     entries = ObjectSortedSets.unmodifiable(sortedMap.reference2CharEntrySet());
   return (ObjectSortedSet<Reference2CharMap.Entry<K>>) entries;
 }
 public ObjectSortedSet<Reference2CharMap.Entry<K>> reference2CharEntrySet() {
   if (entries == null)
     entries = ObjectSortedSets.synchronize(sortedMap.reference2CharEntrySet(), sync);
   return (ObjectSortedSet<Reference2CharMap.Entry<K>>) entries;
 }