Java tutorial
import java.util.Comparator; import java.util.TreeSet; // A reverse comparator for strings. class MyComp implements Comparator<String> { public int compare(String a, String b) { return b.compareTo(a); } } class CompDemo { public static void main(String args[]) { TreeSet<String> ts = new TreeSet<String>(new MyComp()); ts.add("C"); ts.add("A"); ts.add("B"); ts.add("E"); ts.add("F"); ts.add("D"); for (String element : ts) System.out.print(element + " "); } }