@SuppressWarnings("unchecked") public SortedSet<E> headSet(E end){
  return headSet(end,false);
}

@ SuppressWarnings ( "unchecked" ) public SortedSet < E > headSet ( E end ) { return headSet ( end , false ) ; }
answers a sortedset of the specified portion of this treeset which contains elements less than the end element . the returned sortedset is backed by this treeset so changes to one are reflected by the other .
