Simple HashSet

 This  is  a  simple  example of the HashSet .  This is helpful for beginners .  You must  

  focus   the  program output  which  will make sense  how   HashSet work . Order of 

  insertion  is not maintains here   and     no duplicate  element  present in the output.  

import  java.util.HashSet;

/**

 *

 * @author Mukesh Jha

 *

 */

public class SimpleHasSetexample {

           

            public static void main (String[] args) {

                        // TODO Auto-generated method stub

                        HashSet hSet = new HashSet<>();

                       

                hSet.add(1);

                hSet.add(2);

                hSet.add(3);

                hSet.add(7) ;

                hSet.add(9);

                hSet.add(19);

                hSet.add(20);

                hSet.add(19);

                hSet.add(1);

                hSet.add(20);

                System.out.println("HashSet contains.." + hSet);  

            }

}

-->

 Program  output  :------

HashSet contains..[0, 1, 2, 3, 19, 20, 7, 9]