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  1. JDK
  2. JDK-8212970

TZ database in "vanguard" format support

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    Backports

      Description

        Background:

        JDK relies on the time zone data from IANA time zone database. [1] Since last year, they have implemented *negative* save time, e.g., minus one hour in winter from the standard time in summer in Ireland. Another change was the transition time beyond a day period. Example for this is the historic DST in Tokyo, where the transition starts from Saturday 25:00 (which should be translated into the next day (Sunday) at 1am). These changes were disruptive to the JDK, since the implementation never expected the DST to have a negative value, nor transition time beyond a day.

        For such changes to be sunk in, IANA has been providing three formats for the time being, i.e., vanguard/main/rearguard, where vanguard/main contains those changes, while rearguard remains as before, by translating negative savings into positive. However, their latest release, tzdata2019b, stopped providing the rearguard format which JDK has been using for the said reason.

        Changes:

        - In order to support the negative DST, JDK's parser needs to be modified to recognize the vanguard format. The parser looks into the "Zone" and "Rule" entries, and if it finds the negative savings either in the "fixed" saving in the Zone, or a Rule, then it adjusts the standard offset in the Zone and savings in the Rule by that negative amount, so that the compiled time zone data contains only the positive savings. This translation is needed in order for the TZUpdater to use the output "tzdb.dat" file for the previously released JDKs.

        - Transition cutover time beyond 24:00 will be adjusted to fit in 0:00-24:00 by adjusting the transition date.

        - In the discussion occurred on core-libs mailing list before [2], API enhancements were suggested, but not doing so by taking the backward compatibility into consideration.


        [1] https://www.iana.org/time-zones
        [2] http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-October/056167.html

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            backported by

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8231298 TZ database in "vanguard" format support

            • P2 - Crashes, loss of data, severe memory leak.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8231517 TZ database in "vanguard" format support

            • P2 - Crashes, loss of data, severe memory leak.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8231833 TZ database in "vanguard" format support

            • P2 - Crashes, loss of data, severe memory leak.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8307434 TZ database in "vanguard" format support

            • P2 - Crashes, loss of data, severe memory leak.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8231846 TZ database in "vanguard" format support

            • P2 - Crashes, loss of data, severe memory leak.
            • Closed

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8303144 TZ database in "vanguard" format support

            • P2 - Crashes, loss of data, severe memory leak.
            • Closed
            blocks

            Bug - A problem which impairs or prevents the functions of the product. JDK-8212684 TZupdater 2.2.0 not able to update with tzdata2018f release

            • P2 - Crashes, loss of data, severe memory leak.
            • Resolved
            csr for

            CSR - null JDK-8226601 TZ database in "vanguard" format support

            • P3 - Major loss of function.
            • Closed
            duplicates

            Bug - A problem which impairs or prevents the functions of the product. JDK-8195595 Negative daylight saving time breaks tzdata handling

            • P3 - Major loss of function.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8223388 TestZoneInfo310.java fails post tzdata2018i integration

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8259782 Vanguard tzdata support for JDK8u/7u

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved
            relates to

            Bug - A problem which impairs or prevents the functions of the product. JDK-8212684 TZupdater 2.2.0 not able to update with tzdata2018f release

            • P2 - Crashes, loss of data, severe memory leak.
            • Resolved

            Enhancement - null JDK-8230554 TZUpdater support for "vanguard" format (JSR-310 part only)

            • P3 - Major loss of function.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8213393 Clean up copyright headers in test/jdk/sun/util/calendar/zi/tzdata

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8259782 Vanguard tzdata support for JDK8u/7u

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8274864 Remove Amman/Cairo hacks in ZoneInfoFile

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8300097 Possibly wrong DST rules in Europe/Dublin and Africa/Casablanca

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Enhancement - null JDK-8213016 (tz) Upgrade time-zone data to tzdata2018f

            • P3 - Major loss of function.
            • Resolved

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                naoto Naoto Sato
                naoto Naoto Sato
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