AbstractMap.SimpleImmutableEntry<K,V> createSnapshot(){
  V v=getValidValue();
  if (v == null)   return null;
  return new AbstractMap.SimpleImmutableEntry<K,V>(key,v);
}

AbstractMap . SimpleImmutableEntry < K , V > createSnapshot ( ) { V v = getValidValue ( ) ; if ( v == null ) return null ; return new AbstractMap . SimpleImmutableEntry < K , V > ( key , v ) ; }
creates and returns a new simpleimmutableentry holding current mapping if this node holds a valid value , else null .
