[JSR310 M7 Review request] 8007572: Replace existing jdk timezone data at <java.home>/lib/zi with JSR310's tzdb.

[David Holmes]

On 14/03/2013 12:51 PM, Xueming Shen wrote:
> This should have been addessed via
>
> JDK-8008348 *The leftover jdk/make/tools/javazic causes build problems
> with hs25-b19 control job* <https://jbs.oracle.com/bugs/browse/JDK-8008348>

Which is still in the tl repo and unlikely to reach jdk8/jdk8 till b82 
promotion next week.

David

> -Sherman
>
> On 3/13/13 7:19 PM, Andrew Hughes wrote:
>> ----- Original Message -----
>>> The build part of this review looks good to me.
>>>
>> Judging by this changeset, I gather javazic is no longer being run.
>> If so, why is the source code being retained in the tree?  It means
>> that a build of OpenJDK against itself now fails.  The new
>> build system currently finds the javazic source code and tries to
>> compile it,
>> but fails because ZoneInfoFile.java has changed and Gen.java can no
>> longer
>> compile against it.  Deleting the javazic source code fixes the
>> build.
>>
>> Any reason not to commit this?
>>
>> http://cr.openjdk.java.net/~andrew/build/javazic/webrev.01/
>>
>>> /Erik
>>>
>>> On 2013-02-07 19:31, Xueming Shen wrote:
>>>> Hi,
>>>>
>>>> 8007572: Replace existing jdk timezone data at <java.home>/lib/zi
>>>> with
>>>> JSR310's tzdb.
>>>>
>>>> Webrev:
>>>> http://cr.openjdk.java.net/~sherman/8007572/
>>>>
>>>> Note:
>>>> JDK/JRE has been using the time zone data at <java.home>/lib/zi for
>>>> j.u.TimeZone since JDK 1.4.0 [1]. JSR310 has introduced in its own
>>>> time zone data file/format <java.home>lib/tzdb.jar to provide the
>>>> time
>>>> zone data support for its new java.time date-time classes.
>>>>
>>>> So we now have two different time zone data files in different
>>>> formats
>>>> (though from the same time zone data source, Olson tz data, now the
>>>> IANA
>>>> Time Zone Datebase) to support two sets of date-time APIs
>>>> (java.util
>>>> date-time classes and java.time date-time classes) in one JDK/JRE,
>>>> which
>>>> definitely will add the maintenance burden going forward, given the
>>>> fact
>>>> that we will have to update/distribute the latest tzdb data in
>>>> JDK/JRE
>>>> periodically [2].
>>>>
>>>> Also the current way the time-zone data is being
>>>> distributed/installed
>>>> (at <java.home>/lib.zi, as individual file for each time zone) has
>>>> been
>>>> a footprint concern for some configurations, especially the small
>>>> embedded
>>>> environment. The JEP151 [3] was originally submitted to propose to
>>>> store
>>>> the time-zone data more efficiently into a single compressed file.
>>>> The
>>>> JEP 151 has been withdrawn since, with the assumption that JDK 8
>>>> may
>>>> replace the "zi" data with the much smaller JSR310 tzdb data file.
>>>>
>>>> As indicated in JEP151, current installed "zi" directory probably
>>>> takes
>>>> up 1M of disk-space with the 0.5k default file-system-block-size.
>>>> Even
>>>> with the proposed "store in one single compressed file" approach,
>>>> it will
>>>> still take about 250K space for all tzdb data in "zi" directory.
>>>> JSR310
>>>> tzdb data file however is much smaller. It is around 40K for
>>>> compressed
>>>> and 100k uncompressed, for the same tz data.
>>>>
>>>> The proposed change is to share the JSR310 time zone data tzdb.jar
>>>> with j.u.TimeZone by converting the JSR310 tzdb data completely
>>>> (bits
>>>> to bits compatible) at runtime into the internal data structure
>>>> that
>>>> j.u.TimeZone needs for its time zone data functionality/needs.
>>>>
>>>> Thanks!
>>>> -Sherman
>>>>
>>>> [1] https://jbs.oracle.com/bugs/browse/JDK-4230123
>>>> [2]
>>>> http://www.oracle.com/technetwork/java/javase/tzupdater-readme-136440.html
>>>>
>>>> [3] http://openjdk.java.net/jeps/151
>