[tz] Java & Rearguard

Paul Eggert eggert at cs.ucla.edu
Mon Jun 3 06:39:32 UTC 2019

Guy Harris wrote:

>> https://bugs.java.com/bugdatabase/view_bug.do?bug_id=4263805
> Presumably meaning "in theory, Java could be run, on a system that supports the full POSIX syntax for TZ, with TZ set to arbitrary POSIX-compliant values, including values in which clocks are turned *backwards* from standard time in the autumn and winter, but, in practice, that's insufficiently likely that there's any reason to make Java support it".

Yes, it seems that this was reported as a Java bug 20 years ago and ignored on 
the ground that tzdb TZ settings were so much better that there was no need to 
support POSIX TZ settings. Unfortunately, as we've discovered since then, Java 
doesn't fully support tzdb TZ settings either.

It is odd to see the 2016-09-26 comment "Not a popular request" in a bug report 
that has with so many duplicates. Perhaps that was snark?

> Paul, how should we go about requesting an interpretation from TOG here?

I could do that, but I don't see what sort of interpretation is needed. POSIX 
clearly requires support for a TZ setting like 'IST-1GMT0,M10.5.0,M3.5.0/1' that 
specifies negative DST, and that is true regardless of what Ireland happens to 
be doing right now.

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