protected String getFormattedMessage(String key) {
        String value = StringUtils.EMPTY;
        if (remoteBundle != null && remoteBundle.containsKey(key)) {
            value = remoteBundle.getString(key);
        }
        if (StringUtils.isEmpty(value)) {
            value = localBundle.getString(key);
        }
        return value;
    }
@Test
    void getFormattedMessage() {
        ResourceBundleUtil resourceBundleUtil = ResourceBundleUtil.getInstance();
        Assertions.assertThrows(MissingResourceException.class, new Executable() {
            @Override
            public void execute() throws Throwable {
                resourceBundleUtil.getFormattedMessage("NotExist");
            }
        });
        String configErrorMsg = resourceBundleUtil.getFormattedMessage("ERR_CONFIG");
        Assertions.assertEquals("config error, {0}", configErrorMsg);
    }