清空HashSet元素

import java.util.HashSet;

public class RemoveAllElements {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    HashSet hSet = new HashSet();
        hSet.add(new Integer("1"));
        hSet.add(new Integer("2"));
        hSet.add(new Integer("3"));
       
        System.out.println("HashSet before removal : " + hSet);
        hSet.clear();
        System.out.println("HashSet after removal : " + hSet);
        System.out.println("Is HashSet empty ? " + hSet.isEmpty());
}

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