docs: public static Integer getIntValue(Properties cfg, String key) {
        String propValue = cfg.getProperty(key);
        if (propValue == null) {
           return null;
        }
        if (StringHelper.isEmpty(propValue.trim())) {
           throw log.configurationPropertyCantBeEmpty(key);
        } else {
           return parseInt(propValue, 0, "Unable to parse " + key + ": " + propValue);
        }
     }