java.util.HashSet.isEmpty()方法

package com.codingdict;

import java.util.*;

public class HashSetDemo {
   public static void main(String args[]) {

      // create hash set
      HashSet <String> newset = new HashSet <String>();

      // populate hash set
      newset.add("Learning");
      newset.add("Easy");
      newset.add("Simply");  

      // check if the has set is empty
      boolean isempty = newset.isEmpty();

      System.out.println("Is the hash set empty: "+ isempty);
   }    
}