Java tutorial
/* Output: [S, P, G, E] java.util.Collections$ReverseComparator@192d342 * */ import java.util.Collections; import java.util.Set; import java.util.TreeSet; public class MainClass { public static void main(String args[]) throws Exception { String elements[] = { "S", "P", "E", "G", "P" }; Set set = new TreeSet(Collections.reverseOrder()); for (int i = 0, n = elements.length; i < n; i++) { set.add(elements[i]); } System.out.println(set); System.out.println(((TreeSet) set).comparator()); } }