Program: How to copy Map content to another HashMap?

Below example shows how to copy another collection to HashMap. putAll() method helps us to copy another collections to HashMap object.

package com.java2novice.hashmap;

import java.util.HashMap;

public class MyHashMapCopy {

	public static void main(String a[]){
		HashMap<String, String> hm = new HashMap<String, String>();
		//add key-value pair to hashmap
		hm.put("first", "FIRST INSERTED");
		hm.put("second", "SECOND INSERTED");
		hm.put("third","THIRD INSERTED");
		System.out.println(hm);
		HashMap<String, String> subMap = new HashMap<String, String>();
		subMap.put("s1", "S1 VALUE");
		subMap.put("s2", "S2 VALUE");
		hm.putAll(subMap);
		System.out.println(hm);
	}
}

{second=SECOND INSERTED, third=THIRD INSERTED, first=FIRST INSERTED}
{s2=S2 VALUE, s1=S1 VALUE, second=SECOND INSERTED, third=THIRD INSERTED, first=FIRST INSERTED}