HashMap

import java.util.*;

/**
* created by VIKAS SINGH
* on 21 JAN 2016
*/

public class Solution {
	public static void main(String args[]) {
		
		// This is how you declare a HashMap
		HashMap<Integer, String> hm = new HashMap<Integer, String>();
		
		// Adding elements to HashMap
		hm.put(12,"Chaitanya");
		hm.put(7,"Swati");
		hm.put(3,"Neeraj");
		hm.put(16,"Shivani");
		hm.put(17,"Vikas");
		hm.put(3,"Neerajaa");
		
		Set set = hm.entrySet();
		
		Iterator iterator = set.iterator();
		
		while(iterator.hasNext()) {
			Map.Entry me = (Map.Entry) iterator.next();
			System.out.println(me.getKey() + " : " + me.getValue());
		}
		
		System.out.println(hm.get(2));  // it will display null
		
		hm.remove(12);
		
		set = hm.entrySet();
		
		iterator = set.iterator();
		
		while(iterator.hasNext()) {
			Map.Entry me = (Map.Entry) iterator.next();
			System.out.println(me.getKey() + " : " + me.getValue());
		}
		
	}
}