import java.util.TreeSet; public class Main { public static void main(String[] args) { TreeSet<Integer> tSet = new TreeSet<Integer>(); tSet.add(new Integer("1")); tSet.add(new Integer("2")); tSet.add(new Integer("3")); System.out.println("TreeSet before removal : " + tSet); tSet.clear(); System.out.println("TreeSet after removal : " + tSet); System.out.println("Is TreeSet empty ? " + tSet.isEmpty()); } }