code: public static ZoneOffset getZoneOffset(final Calendar self) {
          int offsetMillis = self.get(Calendar.ZONE_OFFSET) + self.get(Calendar.DST_OFFSET);
          return ZoneOffset.ofTotalSeconds(offsetMillis / 1000);
      }
docs: Returns the Time Zone offset of the Calendar as a {@link java.time.ZoneOffset}.
  
  @param self a Calendar
  @return a ZoneOffset
  @since 2.5.0