public static void checkGroup(String group) throws MQClientException {
        if (UtilAll.isBlank(group)) {
            throw new MQClientException("the specified group is blank", null);
        }

        if (group.length() > CHARACTER_MAX_LENGTH) {
            throw new MQClientException("the specified group is longer than group max length 255.", null);
        }


        if (isTopicOrGroupIllegal(group)) {
            throw new MQClientException(String.format(
                    "the specified group[%s] contains illegal characters, allowing only %s", group,
                    "^[%|a-zA-Z0-9_-]+$"), null);
        }
    }
@Test
    public void testGroupNameBlank() {
        try {
            Validators.checkGroup(null);
            fail("excepted MQClientException for group name is blank");
        } catch (MQClientException e) {
            assertThat(e.getErrorMessage()).isEqualTo("the specified group is blank");
        }
    }