Gets the time-zone, such as 'Europe/Paris'.
!(p)
This returns the zone ID. This identifies the time-zone {@link ZoneRules rules}
that determine when and how the offset from UTC/Greenwich changes.
!(p)
The zone ID may be same as the {@linkplain #getOffset() offset}.
If this is true, then any future calculations, such as addition or subtraction,
have no complex edge cases due to time-zone rules.
See also {@link #withFixedOffsetZone()}.
Gets the time-zone, such as 'Europe/Paris'. !(p) This returns the zone ID. This identifies the time-zone {@link ZoneRules rules} that determine when and how the offset from UTC/Greenwich changes. !(p) The zone ID may be same as the {@linkplain #getOffset() offset}. If this is true, then any future calculations, such as addition or subtraction, have no complex edge cases due to time-zone rules. See also {@link #withFixedOffsetZone()}.
@return the time-zone, not null