collections - reversing their order

■ Any List can be reversed by simply calling Collections.reverse( listname );

■ To reverse a Set or an Array you use the form of the appropriate sort(..) method that lets you specify a Comparator to be used. In the sort(obj, comparator) method you specify Collections.reverseOrder( ) which provides a reverse comparator. i.e

Arrays.sort(anarray, Collections.reverseOrder( )); or

Collections.sort(list, Collections.reverseOrder( ));