[tz] Java & Rearguard

Paul Eggert eggert at cs.ucla.edu
Sat Jun 1 07:43:57 UTC 2019

Brandon Smith wrote:

> we now have a situation in which the transition from DST off to DST on
> results in an ambiguous local time period for Ireland.

For what it's worth, this particular situation is not new in tzdata. For 
example, Europe/Kiev has a transition from +03 (without DST) to +02 (with DST) 
on 1941-09-19 at 24:00, which means that timestamps that day between 23:00 and 
24:00 are ambiguous in Kiev. This transition has been present since the release 
of tzdata 1999j two decades ago. I'm sure there are other examples.

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