present object in hashset code example

Example: HashSet contains(Object o) method in java

import java.util.HashSet;
public class HashSetContainsObjectMethodExample
{
   public static void main(String[] args)
   {
      HashSet<String> hs = new HashSet<String>();
      hs.add("hello");
      hs.add("world");
      hs.add("java");
      // check if element exists
      boolean bool = hs.contains("world");
      System.out.println("Is element 'world' exists: " + bool);
   }
}