code: protected void validateFields() {
          for (int field = 0; field < fields.length; field++) {
              if (stamp[field] >= MINIMUM_USER_STAMP) {
                  validateField(field);
              }
          }
      }
docs: Ensure that each field is within its valid range by calling {@link
  #validateField(int)} on each field that has been set.  This method
  should only be called if this calendar is not lenient.
  @see #isLenient
  @see #validateField(int)