8.d implement map in java

import java.util.*; 
class HashMapDemo { 
public static void main(String args[]) 
    { 
        Map<String, Integer> hm = new HashMap<String, Integer>();          hm.put("a", new Integer(100)); 
hm.put("b", new Integer(200)); 
 hm.put("c", new Integer(300)); 
hm.put("d", new Integer(400)); 
        for (Map.Entry<String, Integer> me : hm.entrySet()) { 
            System.out.print(me.getKey() + ":"); 
            System.out.println(me.getValue()); 

        } 

    }