Program: How to copy Set content to another HashSet?

Below example shows how to copy another collection object to HashSet object. By calling addAll() method you can copy another collection to HashSet object.

package com.java2novice.hashset;

import java.util.HashSet;

public class MyHashSetCopy {

	public static void main(String a[]){
		HashSet<String> hs = new HashSet<String>();
		//add elements to HashSet
		hs.add("first");
		hs.add("second");
		hs.add("third");
		System.out.println(hs);
		HashSet<String> subSet = new HashSet<String>();
		subSet.add("s1");
		subSet.add("s2");
		hs.addAll(subSet);
		System.out.println("HashSet content after adding another collection:");
		System.out.println(hs);
	}
}

[second, third, first]
HashSet content after adding another collection:
[s2, s1, second, third, first]