code: public static String requireProperty (Properties props, String key, String missingMessage)
      {
          String value = props.getProperty(key);
          if (StringUtil.isBlank(value)) {
              throw new MissingPropertyException(key, missingMessage);
          }
          return value;
      }
docs: Returns the specified property from the supplied properties object.
  @throws MissingPropertyException with the supplied message if the property does not exist or
  is the empty string.