code: public static MonthDay toMonthDay(final Calendar self) {
          return MonthDay.of(toMonth(self), self.get(Calendar.DAY_OF_MONTH));
      }
docs: Converts the Calendar to a corresponding {@link java.time.MonthDay}. If the Calendar has a different
  time zone than the system default, the MonthDay will be adjusted into the default time zone.
  
  @param self a Calendar
  @return a MonthDay
  @since 2.5.0