docs: private static Calendar parseDateFormat(String s, DateFormat dateFormat,
  											TimeZone tz, ParsePosition pp) {
  		if (tz == null) {
  			tz = DEFAULT_ZONE;
  		}
  		Calendar ret = Calendar.getInstance(tz, Locale.ROOT);
  		dateFormat.setCalendar(ret);
  		dateFormat.setLenient(false);
  
  		final Date d = dateFormat.parse(s, pp);
  		if (null == d) {
  			return null;
  		}
  		ret.setTime(d);
  		ret.setTimeZone(UTC_ZONE);
  		return ret;
  	}