code: public int lengthOfYear() {
  
          try {
              return this.getCalendarSystem().getLengthOfYear(HijriEra.ANNO_HEGIRAE, this.hyear);
          } catch (IllegalArgumentException iae) {
              throw new ChronoException(iae.getMessage(), iae);
          }
  
      }
docs: /*[deutsch]
  <p>Liefert die L&auml;nge des aktuellen islamischen Jahres in Tagen. </p>
  
  @return  int
  @since   3.6/4.4
  @throws  ChronoException if data are not available for the whole year (edge case)