import java.util.HashSet;
import java.util.Iterator;

public class HashSetDemo7 {
    public static void main(String[] args) {
        HashSet set = new HashSet();
        set.add("A");
        set.add("a");
        set.add("B");
        set.add("b");
        System.out.println(set);

        try {
            Iterator iterator = set.iterator();
            while (iterator.hasNext()) {
                System.out.println(iterator.next());
            }

        } catch (Exception e) {
            System.out.println("Exception");

        }

    }

}