Simple Java HashSet example

public class SimpleHashSetExample

   {

     public static void main(String[] args)

     {

       //create object of HashSet

       HashSet hSet = new HashSet();

      

       /*

       Add an Object to HashSet using

       boolean add(Object obj) method of Java HashSet class.

       This method adds an element to HashSet if it is not already present in HashSet.

       It returns true if the element was added to HashSet, false otherwise.

       */

      

       hSet.add(new Integer("1"));

       hSet.add(new Integer("2"));

       hSet.add(new Integer("3"));

      

       /*

       Please note that add method accepts Objects. Java Primitive values CAN NOT

       be added directly to HashSet. It must be converted to corrosponding

       wrapper class first.

       */

      

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

     }

   }