JDK 23 is now in Rampdown Phase One

[Iris Clark]

Per the JDK 23 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 to the jdk23 stabilization branch
(https://github.com/openjdk/jdk/tree/jdk23).  Any changes pushed to
the main line are now bound for JDK 24, as noted previously [3].
Since the repository contains multiple active branches, Reviewers and
Committers must always verify the target branch of each 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 did
for JDK 22 [6]:

  - Most fixes and enhancements intended for the stabilization branch
    will also be applicable to the main line (master branch).
    Integrate such a change into the master branch first.  Then, after
    you have obtained 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 contains more information 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.

  - 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

Iris

[1] https://openjdk.org/projects/jdk/23/#Schedule
[2] https://openjdk.org/projects/jdk/23/#Features
[3] https://mail.openjdk.org/pipermail/jdk-dev/2024-May/009041.html
[4] https://openjdk.org/jeps/3
[5] https://j.mp/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