code: public boolean isField(final String fieldName) {
      if (fieldName != null) {
          return (KEYWORD_LIST.contains(
                  fieldName.toUpperCase(Locale.US))
                  || fieldName.toUpperCase().startsWith(PROP_FIELD));
      }
      return false;
    }
docs: Determines if specified string is a recognized field.
  @param fieldName field name
  @return true if recognized field.