Basic HashSet Operations -Adding elements ,adding duplicates ,removal?

package com.JavaInterview.Programs;

import java.util.HashMap;

import java.util.HashSet;

/*

 * @author:http://javainterviewprograms.blogspot.in/

 * 

 */

public class HashsetTest {

 

 public static void main (String args[])

 {

  HashSet<String> h= new HashSet<String>();

 

 

  h.add("abc");

  h.add("bcd");

 

  System.out.println("hashset sample"+h);

 

  //adding duplicates object

  h.add("abc");

  System.out.println("After adding duplicates key"+h);

 

  //HashSet  size

  System.out.println("HashSet size "+h.size());

 

  //remove elements

  h.remove("abc");

  System.out.println("After removal "+h);

 }

}

Output:

hashset sample[abc, bcd]

After adding duplicates key[abc, bcd]

HashSet size 2

After removal [bcd]