[tz] Welcome to the "tz" mailing list

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Thu May 21 21:42:00 UTC 2020

On 2020-05-21 14:33, Paul Eggert wrote:
> On 5/21/20 9:18 AM, Brian Inglis wrote:
>> System.out.println(java.time.zone.ZoneRulesProvider.getVersions("UTC").keySet());
>> [2019c]
> Thanks for that jshell recipe. I observe the same "2019c" on my Ubuntu 18.04.4
> laptop, even though Ubuntu 18.04.4 has updated tzdata to 2020a, as can be seen
> from this shell command:
> $ zdump -V -c 2020,2021 America/Dawson
> America/Dawson  Sun Mar  8 09:59:59 2020 UT = Sun Mar  8 01:59:59 2020 PST
> isdst=0 gmtoff=-28800
> America/Dawson  Sun Mar  8 10:00:00 2020 UT = Sun Mar  8 03:00:00 2020 MST
> isdst=0 gmtoff=-25200
> So I am observing the same symptoms that Sundar Sarma reports: my tzdata package
> is up-to-date but its Java copy is not.
> There are recipes for fixing the problem by updating the Java copy. 
> For Oracle Java, see
> <https://www.oracle.com/java/technologies/javase/tzupdater-readme.html>. 
> For OpenJDK or some other Java, you can try ZIUpdater
> <https://www.azul.com/products/open-source-tools/ziupdater-time-zone-tool/>,
> tzdbgen <https://github.com/akashche/tzdbgen>,
> and/or IANA Updater <https://bell-sw.com/pages/iana-updater/>. 
> I'm not going to bother to run any of those since I don't normally run Java
> apps on my laptop.
> This Java stuff is all downstream from the tz project proper, so those who have
> problems with it should contact whoever's maintaining the Java software they're
> using.

There should be coordination within each distro about triggering the local Java
package TZ updater when the system tzdata is updated.

My weekly cron tzdata release check script would run the TZ Updater against the
new release if I still had Java and its TZ Updater installed: it's not hard.

Perhaps those with wide deployments of distros with Java packages and apps could
submit bug reports against their distro Java packages to apply TZ updates when
tzdata packages are updated.

Perhaps vendor JVM providers could sponsor packaging their JVM, TZ Updaters, and
applying TZ updates when system tzdata is updated on distros they support using,
rather than leaving it to system or app support or users.

I haven't searched, but apparently even MS Windows now includes tzdata to
support their MS Windows store apps or its infrastructure, and must update that,
along with their proprietary Windows TZ updates.

JVM providers could help more to keep their tzdata up to date, and that could
and should be seen as a competitive advantage.

Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

This email may be disturbing to some readers as it contains
too much technical detail. Reader discretion is advised.
[Data in IEC units and prefixes, physical quantities in SI.]

More information about the tz mailing list