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Get Size of Java HashSet Example

  1. /*
  2.   Get Size of Java HashSet Example
  3.   This Java Example shows how to get the size or nubmer of elements stored in
  4.   Java HashSet object using size method.
  5. */
  6.  
  7. import java.util.HashSet;
  8.  
  9. public class GetSizeOfJavaHashSetExample{
  10.  
  11.   public static void main(String[] args) {
  12.    
  13.     //create HashSet object
  14.     HashSet hSet = new HashSet();
  15.    
  16.     /*
  17.       To get the size of HashSet use
  18.       int size() method of HashSet class. It returns the number of elements
  19.       stored in HashSet object.    
  20.     */
  21.     System.out.println("Size of HashSet : " + hSet.size());
  22.    
  23.     //add elements to HashSet object
  24.     hSet.add(new Integer("1"));
  25.     hSet.add(new Integer("2"));
  26.     hSet.add(new Integer("3"));
  27.  
  28.     System.out.println("Size of HashSet after addition : " + hSet.size());
  29.    
  30.     //remove one element from HashSet using remove method
  31.     hSet.remove(new Integer("1"));
  32.     System.out.println("Size of HashSet after removal : " + hSet.size());
  33.   }
  34. }
  35.  
  36. /*
  37. Output would be
  38. Size of HashSet : 0
  39. Size of HashSet after addition : 3
  40. Size of HashSet after removal : 2
  41. */