Remove all elements from Java HashSet example

This Java Example shows how to remove all elements contained in Java HashSet or clear HashSet object using clear method. It also shows how  to check whether HashSet object is empty or not using isEmpty method.

import java.util.HashSet;

public class RemoveAllElementsFromHashSetExample {

 public static void main(String[] args) {

  // create object of HashSet
  HashSet hSet = new HashSet();

  // add elements to HashSet object
  hSet.add(new Integer("1"));
  hSet.add(new Integer("2"));
  hSet.add(new Integer("3"));

  System.out.println("HashSet before removal : " + hSet);

  /**
   * To remove all elements from Java HashSet or to clear HashSet object
   * use, void clear() method. This method removes all elements from
   * HashSet.
   **/

  hSet.clear();
  System.out.println("HashSet after removal : " + hSet);

  /**
   * To check whether HashSet contains any elements or not use boolean
   * isEmpty() method. This method returns true if the HashSet does not
   * contains any elements otherwise false.
   **/

  System.out.println("Is HashSet empty ? " + hSet.isEmpty());

 }
}

The output is:



HashSet before removal : [1, 2, 3]
HashSet after removal : []
Is HashSet empty ? true