Gets the system default time-zone.
!(p)
This queries {@link TimeZone#getDefault()} to find the default time-zone
and converts it to a {@code ZoneId}. If the system default time-zone is changed,
then the result of this method will also change.
@return the zone ID, not null
@throws DateTimeException if the converted zone ID has an invalid format
@throws ZoneRulesException if the converted zone region ID cannot be found
Gets the system default time-zone. !(p) This queries {@link TimeZone#getDefault()} to find the default time-zone and converts it to a {@code ZoneId}. If the system default time-zone is changed, then the result of this method will also change.
@return the zone ID, not null @throws DateTimeException if the converted zone ID has an invalid format @throws ZoneRulesException if the converted zone region ID cannot be found