java.util.HashSet.contains() 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 the existence of element
      boolean exist = newset.contains("Simply");

      System.out.println("Is the element 'Simply' exists: "+ exist);
   }    
}