Get Size of HashSet : HashSet « Collections « Java Tutorial

1. Java Tutorial
2. Collections
3. HashSet

import java.util.HashSet;

public class Main {
  public static void main(String[] args) {
    HashSet<Integer> hSet = new HashSet<Integer>();
    System.out.println("Size of HashSet : " + hSet.size());

    hSet.add(new Integer("1"));
    hSet.add(new Integer("2"));
    hSet.add(new Integer("3"));

    System.out.println(hSet.size());

    hSet.remove(new Integer("1"));
    System.out.println(hSet.size());
  }
}
/*
Size of HashSet : 0
3
2
*/