* @param zone time zone to apply, or default if null
* @return a MutableDateTime using the same millis
*/
public MutableDateTime toMutableDateTime(DateTimeZone zone) {
Chronology chrono = DateTimeUtils.getChronology(getChronology());
chrono = chrono.withZone(zone);
return new MutableDateTime(getMillis(), chrono);
}
/**
* Get this object as a MutableDateTime using the given chronology and its zone.