JDK 18 enters Rampdown Phase One next week

[mark.reinhold at oracle.com]

JDK 18 enters Rampdown Phase One next week on Thursday, 9 December.
Changes intended for JDK 18 should be in the main-line repository
(https://github.com/openjdk/jdk) by 16:00 UTC on that day [1].

At that time we’ll fork the main line to the JDK 18 stabilization
repository, jdk18, and promote next week’s build and all remaining
JDK 18 builds from there.

We’ll semi-automatically merge changes pushed to jdk18 into the
main-line repository, as we have in previous feature-release
transitions.  This means that:

  - If you make a change in JDK 18 then you needn’t do any extra
    work to get it into the main line, though if a merge conflict
    arises then you might be asked to help resolve it.

  - If you need to make a change in both JDK 18 and the main line
    then just push it to JDK 18, and wait for the automatic merge
    to complete.

Changes pushed to the main line after 16:00 UTC next Thursday will
be bound for JDK 19 only, unless they’re subsequently back-ported
to JDK 18.

The Rampdown Phase One process is defined in JEP 3 [2].

To answer a potential FAQ, again: Now that we’ve moved over to Git,
why don’t we just use a branch in the main-line repository for JDK
18 stabilization work?  A few of us have given that some thought,
but a change of that scope requires a fair amount of preparation
and coordination.  We hope to revisit that option for JDK 19.

- Mark


[1] https://time.is/1600_9_December_2021_in_UTC/Stockholm/London/Boston/San_Francisco?JDK_18_Rampdown_Phase_One
[2] https://openjdk.java.net/jeps/3