code: public static String requireNotEmpty(String obj, String errorText) {
      if (isBlank(obj)) {
        throw new IllegalArgumentException(errorText);
      }
      return obj;
    }
docs: Ensures that {@code obj} isn't {@code null} or an empty string.
  
  @param obj
  The parameter to check.
  @param errorText
  The exception message.
  @throws IllegalArgumentException
  If {@code obj} is {@code null} or an empty string.