class SetUtil {

	public static <S, T extends S, U extends S> boolean differenceNotEmpty(final Collection<T> a, final Collection<U> b) {
		if (b == null) {
			return !a.isEmpty();
		}
		for (S item : a) {
			if (!b.contains(item)) {
				return true;
			}
		}
		return false;
	}

	private  SetUtil();

}