Java diff HashMap and Hashtable

import java.util.Collection;

import java.util.HashMap;

import java.util.Iterator;

import java.util.Map;

import java.util.Set;



public class HashMap_HashTable {

   public static void main(String args[]) {

      // Create a hash map

      HashMap hm = new HashMap();



      // Put elements to the map

      hm.put("Zara", new Double(3434.34));

      hm.put("Mahnaz", new Double(123.22));

      hm.put("Ayan", new Double(1378.00));

      hm.put("Daisy", new Double(99.22));

      hm.put("Qadir", new Double(-19.08));

      // Get a set of the entries

      Set set = hm.entrySet();

      // Get an iterator

      Iterator i = set.iterator();



      // Display elements

      while(i.hasNext()) {

         Map.Entry me = (Map.Entry)i.next();

         System.out.print(me.getKey() + ": ");

         System.out.println(me.getValue());

      }

      System.out.println();

      // Deposit 1000 into Zara's account

      double balance = ((Double)hm.get("Zara")).doubleValue();

      hm.put("Zara", new Double(balance + 1000));

      System.out.println("Zara's new balance: " + hm.get("Zara"));

      HashMap< String, String> hMap = new HashMap< String, String>();

      hMap.put("1", "1st");

      hMap.put("2", "2nd");

      hMap.put("3", "3rd");

      Collection cl = hMap.values();

      Iterator itr = cl.iterator();

      while (itr.hasNext()) {

         System.out.println(itr.next());

      }

   }

}