WithZoneSameLocal

withZoneSameLocal is a method of the Java time API, most commonly used on ZonedDateTime. It returns a new ZonedDateTime by keeping the same local date and time fields (year, month, day, hour, minute, second, and nanosecond) but applying a different time zone. In other words, it preserves the wall-clock value and interprets it in the target zone.

The key effect is that the resulting instant (the absolute point in time) may change. Since different zones have different offsets from UTC, changing the zone while keeping the local date-time constant can move the corresponding instant forward or backward. This is in contrast to withZoneSameInstant, which keeps the same instant and adjusts the local date-time to reflect the new zone.

Usage guidance: use withZoneSameLocal when you want to reinterpret the same wall-clock time in another zone. This is useful for display or user input scenarios where the local time value should be preserved while changing context to a different zone. Be aware that DST transitions can complicate resolution: the local date-time might be invalid or ambiguous in the target zone, potentially causing exceptions or different offset behavior depending on the zone’s rules.

Example (conceptual): starting from a ZonedDateTime representing 2022-03-27T12:00 in Europe/Paris, calling withZoneSameLocal(ZoneId.of("America/New_York")) yields a ZonedDateTime with 12:00 in America/New_York, but the underlying instant reflects the offset used by that zone at that local time.

See also: withZoneSameInstant, ZoneId, ZoneRules.