import java.util.HashSet;
import java.util.Iterator;
public class HashsetDemo{
 public static void main(String[] args){
  HashSet hash = new HashSet();
  hash.add(\"a\");
  hash.add(\"b\");
  hash.add(\"c\");
  Iterator it = hash.iterator();
  while(it.hasNext()){
   System.out.println(it.next());
  }
 }
}