01: package java.util; 02: 03: public interface SortedSet extends Set { 04: Comparator comparator(); 05: 06: Object first(); 07: 08: SortedSet headSet(Object toElement); 09: 10: Object last(); 11: 12: SortedSet subSet(Object fromElement, Object toElement); 13: 14: SortedSet tailSet(Object fromElement); 15: }