import java.util.*; public class HelloWorldSet { public static void main(String[] args) { try { // HashSet Set hashSet = new HashSet(); addData(hashSet); System.out.println("HashSet : " + hashSet); // TreeSet Set treeSet = new TreeSet(); addData(treeSet); System.out.println("TreeSet : " + treeSet); // LinkedHashSet Set linkedHashSet = new LinkedHashSet(); addData(linkedHashSet); System.out.println("LinkedHashSet : " + linkedHashSet); } catch (Exception e) { e.printStackTrace(); } } static void addData(Set set) { for (int i = 10;i >= 1;i--) { set.add(new Integer(i)); } } }