sample12.java

import java.util.*;
public class sample12 {
 public static void main(String[] args)
 {
 TreeMap hm=new TreeMap<>(); // follow order indexing wont follow duplicates
 hm.put(109, "Acon");
 hm.put(102,"Bcon");
 hm.put(103,"Ccon");
 hm.put(104,"Dcon");
 hm.put(105,"Econ");
 hm.put(106,"Fcon");
 hm.put(1,"Zcon");
 hm.put(1,"Fcon");
 Set s= hm.keySet();
 Iterator itr = s.iterator();
 while(itr.hasNext())
 {
 Object o=itr.next();
 System.out.println(o + " ===" + hm.get(o));
 }
 
 }
}