public static <K, V> boolean isNullOrEmpty(Map<K, V> map) {
        return map == null || map.isEmpty();
    }
@Test
    public void isNullOrEmpty_whenNotEmpty() {
        Map<String, String> map = new HashMap<>();
        map.put("a", "b");
        assertFalse(MapUtil.isNullOrEmpty(map));
    }