import java.util.Collections; import java.util.HashSet; public class Main { public static void main(String[] args) { HashSet<Long> hashSet = new HashSet<Long>(); hashSet.add(new Long("1111111111")); hashSet.add(new Long("2222222222")); hashSet.add(new Long("3333333333")); hashSet.add(new Long("4444444444")); hashSet.add(new Long("5555555555")); Object obj = Collections.max(hashSet); System.out.println(obj); } }