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Adjust java/java-devel requires to multi-vendor JDK world and replace legacy JDKs by third party Eclipse Temurin repositories

This is a proposed Change for Fedora Linux.
This document represents a proposed Change. As part of the Changes process, proposals are publicly announced in order to receive community feedback. This proposal will only be implemented if approved by the Fedora Engineering Steering Committee.

Summary

Adjust java/java-devel provides/requires to multivendor world and obsolete all non-system LTS JDKs (java-1.8.0-openjdk, java-11-openjdk, java-17-openjdk in time of writing) by appropriate, properly integrating, RPMs from Eclipse Adoptium repositories.

Owner


Current status

  • Targeted release: Fedora Linux 42
  • Last updated: 2024-09-24
  • Writing in progress
  • Announced
  • Discussion thread
  • FESCo issue: <will be assigned by the Wrangler>
  • FESCo exception/denial to enable temurin repos by default: todo by maintainer once appropriate
  • Tracker bug: <will be assigned by the Wrangler>
  • Release notes tracker: <will be assigned by the Wrangler>

Expected schedule

As 'Change Checkpoint: Proposal submission deadline (System Wide Changes) Tue 2024-12-24' and 'Branch Fedora Linux 42 from Rawhide Tue 2025-02-04' is in reasonable time, we hope to finish all peacefully (as all initial tests are already finished).

Detailed Description

Fedora currently ships:

  • java-1.8.0-openjdk (LTS)
  • java-11-openjdk (LTS)
  • java-17-openjdk (LTS)
  • java-21-openjdk (LTS), system JDK
  • java-latest-openjdk (STS) - currently JDK22, soon JDK23, in time of finish JDK24
  • In future, java-25-openjdk will fork from java-latest-openjdk, and will become system jdk, as jdk21 before (https://fedoraproject.org/wiki/Changes/Java21#java-21-openjdk_as_the_system_JDK_in_F40) and jdk17 before that and so on...
    • java-21-openjdk will then follow the fate of java-17-openjdk, 11 and 1.8.0 as written lower.

We, OpenJDK maintainers in Fedora, would like to orphan/close/obsolete non system JDKs in favor of Temurin JDKs. Adoptium Temurin (https://adoptium.net/temurin/releases/) is de-facto standard build of JDK, with huge support and compatibility, and all current Fedora JDK contributors are long term members and contributors to Temrun JDK (and its RPMs). Adoptium is dedicated, to keep Temurin RPMs well integrated and healthy for Fedora. Adoptium efforts are tracked in https://github.com/adoptium/installer/issues/848 . Adoptium is maintaining theirs repos (https://adoptium.net/installation/linux/#_centosrhelfedora_instructions) for ages, and they're heavily used.

Practically We see several approaches:

  • provide rpm which will contain the 3d party repository\
    • integrate it with gnome software and and fedora setup of 3rd party repos
    • we would like try to do an fluent transition - so the current 8,11 and 17 packages will also install the rpm wiht repository files and thus once we remove jdk8-17 (or future) from distribution, they will be smoothly updated by temurin jdk (with check if other 3rd party repos are enabled)

java-latest-openjdk remain also maintained in Koji, as it is necessary testing ground for future system JDK.

It was never an intention to repack a binary Temurin blob in Koji (just in case anybody will think about it). It is not an intention to get rid of maintaining System JDK. However once JDK will no longer be System jdk in any live Fedora, it will be orphaned/closed in favor of Temurin JDK. So once f42 will go out we will continue to maintain only jdk 23+21. In some short time, we will maintain 25+21, a bit alter 26+25+21... And once 25 will become system JDK in all live fedoras, we will ditch 21 in favor of Temurins

java packages requires mass change

The javastack (via javapackages-tools) will be reworked to:

  • encapsulate dependencies on system jdk (or any other koji-based jdk) to javapackages tools
  • allow any application to work on any, even 3rd party java

This should be achieved via following chnages to reqires changes and generated changes:

  • javapackages-local for packages with ant or no build - requires java-%{system}-openjdk-devel (%jpackage_script)
    • javapavckages-local%VERSIONED for older ones
    • For slower transitions to newer jdks
  • javapackages-tools
    • requires java-%{system}-openjdk-headless
    • javapackages-tools%VERSIONED for older ones
    • Do not requires java-%{system}-openjdk
      • Will not be added - satisfied by Javapackages-tools with java || java-xyz-openjdk requires
  • Requires generator which crawls through launchers of packages (including jpackage_script ) which source java_functions
    • will be pointing to used jre headless
    • %jpackage_script is implicitly affected by generator and will generate requires to corresponding %{build_time_sdk's}-headless jre (which is currently system jdk, which is jdl 21, unless specified differently)
  • Other packages will need to manually adjust from java-%{system}-openjdk-/headless/devel to java-(system+1)-openjdk-/headless/devel
    • This affects mass rebuilds (instead of just release++ a java-xy-openjdk must do xy++). Positive si that there is more time to do that
    • Indirectly this is not enforcing new system jdk when new LTS is promoted in Fedora
      • Otherwise generic java-devel will no longer satisfy new systemjdk after system bump
  • JAVA_HOME remains main override (rpm generated requires are not affected (maybe todo?))


https://docs.fedoraproject.org/en-US/packaging-guidelines/Java/ will be adjusted accordingly

the packages built by pure javac or jsut build requires java without any javapackages tools will be adjsuted manually

Note, that this is much smaller effort then it looks like. 99% of packages are living with generated provides, and will get the change automagically. The remaining - aprox 10 - packages will be handled manually

Feedback

todo

Benefit to Fedora

The number of legacy JDKs have grown, and hand in hand with that the number of theirs usages dropped to minimum. It seems there is no longer any need to maintain them, as theirs usage is only highly specialized. By providing 3rd party repo, we allow the specialized use-cases to continue to exist. By discontinuing theirs build in koji we well untie or hands to move forward and focus on future JDKs. Also we will enable fedora to provide highly stable, often updated, secure, 100% integrate-able and passionately maintained builds of legacy JDKs, which will serve as proper replacement if really needed. As a side effect of the changes in provides/requires, we will allow every JDK, from any vendor, which follows unofficial packaging JEP (which covers java and javac alternatives master and java/java-devel provides) to be effectively part of system if wanted, and not just silent companion.

Scope

  • Proposal owners:
    • will provide and maintain the 3rd party repo - https://bugzilla.redhat.com/show_bug.cgi?id=2313339
    • will help to integrate it with gnome-software and other 3rd party repos units
    • will orphan or replace (based on agreement on details
    • will update java packages documentation
    • we will fix all the direct requires java/java-devel (aprox 14 only)
    • we will communicate with packagers of known, remainingm packages which do not run with system jdk (aprox 5 )
  • Other developers:
    • javapackages-tools, maven and ant maintainers are already on board to to totally decuple system jdk from installed java
  • Policies and guidelines: N/A (not needed for this Change)
    • java packaging guidelines will be updated
  • Trademark approval: N/A (not needed for this Change)
  • Alignment with the Fedora Strategy:
    • This proposal is aligned with Fedora mission - to be on top of technology. We want to focus on newer JDKs, and still provide comfortable access to legacy ones,

Upgrade/compatibility impact

No meter what approach will be selected at the end, there will be upgrade impact.

  • in ideal usecase, the JDKs from koji simply replaces themselves by those from Eclipse Temurin
  • in worst case, user will just get disabled 3rd party repo and updated docs.

In all cases system jdk will remain on machine, and in all cases legacy jdks will be replaced or disappear. I would really be unhappy to simply discontinue them, and leave unmaintained software on target boxes.


Early Testing (Optional)

Do you require 'QA Blueprint' support? Y

How To Test

No JDK on system

  1. get system without java
  2. update to next fedora
  3. no JDK should be there

Only system JDK on system and future STS jdk

  1. get system with system jdk only
  2. update to next fedora
  3. JDK should be there

Only legacy JDK

  1. get system withotu any JDK
  2. manually install any of legacy LTS jdks
  3. update to next fedora
  4. the legacy jdk should not be there or should be gone

System JDK and legacy JDK

  1. get system with system jdk only
  2. manually install any of legacy LTS jdks
  3. update to next fedora
  4. system JDK should be there
  5. the legacy jdk should not be there or should be gone


User Experience

As already described, basic users should not notice change. Advanced users should not lost.

Dependencies

Several (less then 10) packages will lost theirs main dependencies. Those list will be enumerated. Those packages will need to orphan and move to different kind of distribution or update. Main java stack - the packages depending on system java/java-devel/java-headless/java-packages-tools and similar, should not notice change.

Contingency Plan

  • Contingency mechanism: If we fails to introduce Eclipse Temurin JDKs repo, we will simply orphan legacy JDKs as written earlier
  • Contingency deadline: 1. December 2024
  • Blocks release? Yes


Documentation

Only eclipse temurin install pages and java packages guidelines

  • todo link1
  • todo link2

Release Notes

tbd

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