JDK 24 is now in Rampdown Phase One

[Mark Reinhold]

Per the JDK 24 schedule [1], we are now in Rampdown Phase One.

The overall feature set [2] is frozen.  No further JEPs will be
targeted to this release.

We’ve branched the main line of development, in the master branch, to
create the jdk24 stabilization branch:

  https://github.com/openjdk/jdk/tree/jdk24

Any changes pushed to the master branch are now bound for JDK 25, as
noted previously [3].  Since the repository contains multiple active
branches, Reviewers and Committers should carefully verify the target
branch of every pull request.

The stabilization branch is open for select bug fixes and, with
approval, late enhancements per JEP 3, the JDK Release Process [4].
If you’re responsible for any of the bugs on the RDP 1 candidate-bug
list [5] then please see JEP 3 for guidance on how to handle them.

We will integrate most stabilization changes via backports, as we have
since JDK 22 [6]:

  - Most fixes and enhancements intended for the stabilization branch
    will also be applicable to the main line, in the master branch.
    Integrate such a change into the master branch first.  Then, after
    you obtain any required approvals, backport it to the stabilization
    branch using the Skara `/backport` command [7] or, if necessary, by
    manually opening a backport PR with the title `Backport $HASH`,
    where `$HASH` is the original commit hash.  (The Developers’ Guide
    has guidance on working with branches [8] and backports [9].)

  - Some fixes will be specific to the stabilization branch and not
    applicable to the main line.  Integrate such fixes directly into the
    stabilization branch.

In order to make sure that no backports are missed, prior to the RDP 2
and RC phases we will remind JDK Contributors to review changes that
have been integrated into the main line but not backported to the
stabilization branch.  These JBS queries can be useful:

  - Changes not backported from the main line
    https://bugs.openjdk.org/issues/?filter=44264

  - My changes not backported from the main line
    https://bugs.openjdk.org/issues/?filter=44268

- Mark


[1] https://openjdk.org/projects/jdk/24/#Schedule
[2] https://openjdk.org/projects/jdk/24/#Features
[3] https://mail.openjdk.org/pipermail/jdk-dev/2024-November/009664.html
[4] https://openjdk.org/jeps/3
[5] https://openjdk.org/s/jdk-rdp-1
[6] https://openjdk.org/jeps/3#Integrating-fixes-and-enhancements
[7] https://wiki.openjdk.org/display/SKARA/Backports
[8] https://openjdk.org/guide/#working-with-git-branches
[9] https://openjdk.org/guide/#working-with-backports-in-jbs