Iterating Map

package com.usr.collections;

import java.util.Collection;

import java.util.HashMap;

import java.util.Iterator;

import java.util.Map;

import java.util.Set;

public class LoopingMap {

       public static void main(String[] args) {

              Map<Integer, String> hm = new HashMap<Integer, String>();

              hm.put(1, "sunday");

              hm.put(2, "monday");

              hm.put(3, "tueday");

              hm.put(4, "wednesday");

              hm.put(5, "thursday");

              hm.put(6, "friday");

              hm.put(7, "saturday");

              System.out.println("1.Using for each loop");

              for (Map.Entry<Integer, String> entry : hm.entrySet()) {

                     System.out.println(entry.getKey() + ":" + entry.getValue());

              }

              System.out.println("2.Retriving keys and values ");

              Set<Integer> set = hm.keySet();

              Iterator<Integer> itr = set.iterator();

              while (itr.hasNext()) {

                     Integer key = (Integer) itr.next();

                     System.out.println(key + ":" + hm.get(key));

              }

              System.out.println("3.Retrieving values");

              Collection<String> col = hm.values();

              Iterator<String> itr1 = col.iterator();

              while (itr1.hasNext()) {

                     String value = (String) itr1.next();

                     System.out.println(value + ":");

              }

              System.out.println("4.Retrieving keys and values using Iterator");

              Iterator<Map.Entry<Integer, String>> entries = hm.entrySet().iterator();

              while (entries.hasNext()) {

                     Map.Entry<Integer, String> entry = entries.next();

                     System.out.println(entry.getValue() + ":" + entry.getKey());

              }

       }

}