Java Program to compare two sets and retain elements which are same

import java.util.*;
public class demo1 
{
 public static void main(String[] args)
 {
   HashSet<String> hash_set = new HashSet<String>();
   hash_set.add("C#");
   hash_set.add("C++");
   hash_set.add("Java");
   hash_set.add("Python");
   hash_set.add("Perl");
   hash_set.add("Ruby");
   System.out.println("Frist HashSet content: "+hash_set);
       
   HashSet<String>hash_set1 = new HashSet<String>();
   hash_set1.add("C#");
   hash_set1.add("C++");
   hash_set1.add("Python");
   hash_set1.add("Perl");
   hash_set1.add("HTML");
   System.out.println("Second HashSet content: "+hash_set1);
         
   hash_set.retainAll(hash_set1);
   System.out.println("HashSet content:");
   System.out.println(hash_set);
  }
}