public static void main(String[] args) {
        Set<Integer> c = new HashSet<Integer>() {
        };
        for (int i = 0; i < 10; i++) {
            c.add(i);
            c.add(i+2); //demonstrate how the Set works. Only unique added.
        }

        for (Integer i : c) {
            System.out.print(i + ", ");
        }
    }