Hashmap

 import java.util.*;
 class HashMapContoh{
     public static void main(String args[]){
         //membuat hashmap
         HashMap<Integer,String> hm=new HashMap<Integer,String>();
         //input objek
         hm.put(100,"Kano");
         hm.put(101,"Laila");
         hm.put(102,"Badu");
         hm.put(null, "Johan");
         //menampilkan isi
         for(Map.Entry m:hm.entrySet()) {
             System.out.println(m.getKey()+" "+m.getValue());
         }
     }
 }