static boolean isValidIpEntity(String ip) {
        if (ip == null) return true;
        try {
            InetAddress.getByName(ip);
            return true;
        } catch (UnknownHostException e) {
            return false;
        }
    }
@Test
    public void testIsValidIpEntityWithNull() {
        assertTrue(ClientQuotaControlManager.isValidIpEntity(null));
    }