public static UUIDUtils getInstance() {
        return ID_WORKER_UTILS;
    }
@Test
    public void testConstructor() throws Exception {
        Class<?> uUIDUtilsClass = UUIDUtils.getInstance().getClass();
        Class<?>[] p = {long.class, long.class, long.class};
        Constructor<?> constructor = uUIDUtilsClass.getDeclaredConstructor(p);
        constructor.setAccessible(true);
        try {
            constructor.newInstance(-1L, 10L, 10L);
        } catch (InvocationTargetException ex) {
            assertTrue(ex.getCause().getMessage().startsWith("worker Id can't be greater than"));
        }

        try {
            constructor.newInstance(10L, -1L, 10L);
        } catch (InvocationTargetException ex) {
            assertTrue(ex.getCause().getMessage().startsWith("datacenter Id can't be greater than"));
        }
    }