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Remove specified element from Java HashSet example

  1. /*
  2.   Remove specified element from Java HashSet example
  3.   This Java Example shows how to remove a specified object or element
  4.   contained in Java HashSet object using remove method.
  5. */
  6.  
  7. import java.util.HashSet;
  8.  
  9. public class RemoveSpecifiedElementFromHashSetExample {
  10.  
  11.   public static void main(String[] args) {
  12.  
  13.     //create object of HashSet
  14.     HashSet hSet = new HashSet();
  15.    
  16.     //add elements to HashSet object
  17.     hSet.add(new Integer("1"));
  18.     hSet.add(new Integer("2"));
  19.     hSet.add(new Integer("3"));
  20.    
  21.     System.out.println("HashSet before removal : " + hSet);
  22.    
  23.     /*
  24.       To remove an element from Java HashSet object use,
  25.       boolean remove(Object o) method.
  26.       This method removes an element from HashSet if it is present and returns
  27.       true. Otherwise remove method returns false.
  28.     */
  29.    
  30.     boolean blnRemoved = hSet.remove(new Integer("2"));
  31.     System.out.println("Was 2 removed from HashSet ? " + blnRemoved);
  32.    
  33.     System.out.println("HashSet after removal : " + hSet);
  34.   }
  35. }
  36.  
  37. /*
  38. Output would be
  39. HashSet before removal : [3, 2, 1]
  40. Was 2 removed from HashSet ? true
  41. HashSet after removal : [3, 1]
  42. */