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<!-- The actual name of your proposed change page should look something like: Changes/Your_Change_Proposal_Name.  This keeps all change proposals in the same namespace -->
= Drop Mandatory Requires on JRE =
{{Change_Proposal_Banner}}
== Summary ==
== Summary ==
Drop the requirement of Java libraries to have Requires on JREs.
<!-- A sentence or two summarizing what this change is and what it will do. This information is used for the overall changeset summary page for each release. Note that motivation for the change should be in the Benefit to Fedora section below, and this part should answer the question "What?" rather than "Why?". -->
Drop the requirement of Java libraries to have Requires on JREs.  


== Owner ==
== Owner ==
* Name: [[User:mkoncek|Marián Konček]]
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* Name: [[User:mkoncek| Marián Konček]]
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* Email: <mkoncek@redhat.com>
* Email: mkoncek@redhat.com
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* FESCo shepherd: [[User:FASAccountName| Shehperd name]] <email address>
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== Current status ==
== Current status ==
== Detailed description ==
[[Category:ChangeReadyForFesco]]
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<!-- [[Category:SelfContainedChange]] -->
[[Category:SystemWideChange]]
 
* Targeted release: [https://docs.fedoraproject.org/en-US/releases/f41/ Fedora Linux 41]
* Last updated: <!-- this is an automatic macro — you don't need to change this line -->  {{REVISIONYEAR}}-{{REVISIONMONTH}}-{{REVISIONDAY2}}
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* [https://lists.fedoraproject.org/archives/list/devel-announce@lists.fedoraproject.org/thread/MPQ76CVP53Z4SBTGIPV3V5S76CBUKRMJ/ Announced]
* [https://discussion.fedoraproject.org/t/f41-change-proposal-drop-mandatory-requires-on-jre-system-wide/114186 Discussion Thread]
* FESCo issue: [https://pagure.io/fesco/issue/3207 #3207]
* Tracker bug: <will be assigned by the Wrangler>
* Release notes tracker: <will be assigned by the Wrangler>
 
== Detailed Description ==
<!-- Expand on the summary, if appropriate.  A couple sentences suffices to explain the goal, but the more details you can provide the better. -->
Current [https://docs.fedoraproject.org/en-US/packaging-guidelines/Java/#_buildrequires_and_requires guidelines] require all Java packages to `Require: java-headless or java-headless >= 1:minimal_required_version`.
 
Our aim is to drop this explicit requirement on Java library packages. The requirement should stay for Java applications.
 
=== Context ===
Java packages are compiled using `javac` into `.class` files and composed into `.jar` archives. Jar archives can be used as compile or runtime dependencies for other packages or can be directly executed with the java command provided by a JRE.
 
Jar archives can be executed using the command: `java -jar ${FILE}`. This command executes the `main` method either specified via CLI or specified within the Jar manifest file.
 
Java packages, which serve as libraries only, lack the `main` method and are not executable. Therefore, there is no requirement on any specific JRE imposed by the library implicitly.
 
=== Different JDKs ===
This proposal is also related to the topic of different JDKs. Developers may want to use or build packages which use a JDK different than the one provided by the `java-<N>-openjdk` package. After this proposal was implemented, they would be able to depend on Java library packages with no introduction of the OpenJDK package.
 
=== Rationale ===
Java libraries are more similar to native libraries than to libraries written in dynamic scripting languages. They are compiled to a bytecode and are not executable. Java libraries can be used as dependencies for any Java application and there is no implicit dependency on the system default JDK.
 
Java applications, on the other hand, are expected to be tested and to work with the system JDK and from the user's perspective: after installing an application they must be able to simply run the binary. Therefore the `Requires` on the system JDK is kept for Java applications.
 
== Feedback ==
== Feedback ==
<!-- Summarize the feedback from the community and address why you chose not to accept proposed alternatives. This section is optional for all change proposals but is strongly suggested. Incorporating feedback here as it is raised gives FESCo a clearer view of your proposal and leaves a good record for the future. If you get no feedback, that is useful to note in this section as well. For innovative or possibly controversial ideas, consider collecting feedback before you file the change proposal. -->
== Benefit to Fedora ==
== Benefit to Fedora ==
== Scope/Proposal owners ==
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      Does this improve some specific package or set of packages?
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      Does this improve specific Spins or Editions?
          For example: This change modifies the default install of Fedora Workstation to be more in line with the base install of Fedora Server.
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          For example: Ensuring that a minimal set of tools required for contribution to Fedora are installed by default eases the onboarding of new contributors.
 
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    https://fedoraproject.org/wiki/Changes/Annobin (low-level and technical, invisible to users)
    https://fedoraproject.org/wiki/Changes/ParallelInstallableDebuginfo (low-level, but visible to advanced users)
    https://fedoraproject.org/wiki/Changes/VirtualBox_Guest_Integration (primarily a UX change)
    https://fedoraproject.org/wiki/Changes/NoMoreAlpha (an improvement to distro processes)
    https://fedoraproject.org/wiki/Changes/perl5.26 (major upgrade to a popular software stack, visible to users of that stack)
-->
* Very little user-visible benefit.
* Reduced dependencies of Java packages.
* Simplified maintenance of Java packages.
** Smaller impact of JDK major updates (e.g. `1.8.0 -> 11 -> 17 -> 21`). Introducing a new system version of JDK requires the rebuild of each Java package in order to have updated `Requires` to contain the newest version.
 
== Scope ==
* Proposal owners:
<!-- What work do the feature owners have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
** Find all Java applications in Fedora, i.e. packages which `BuildRequire` `java-devel / maven-local / ant` and at the same time install files into `/bin` or `/sbin` or `/usr/bin` or `/usr/sbin`.
** Open pull requests adding `Requires: java-headless` into their `.spec` file.
** Remove `Requires` generator from [https://src.fedoraproject.org/rpms/javapackages-tools/blob/8714cc1d03d3f31251539c3fca53383b822834bc/f/javapackages-config.json#_5 javapackages-tools]
** Wait for a mass rebuild.
 
* Other developers: <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
<!-- What work do other developers have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
** Maintainers of Java applications will need to add an explicit `Requires: java-headless` field into their `.spec` file or a specific version of thereof (such as `java-17-openjdk-headless`).
 
* Release engineering: [https://pagure.io/releng/issue/12069 #12069] <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
<!-- Does this feature require coordination with release engineering (e.g. changes to installer image generation or update package delivery)?  Is a mass rebuild required?  include a link to the releng issue.
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** Mass rebuild is not required, this change can propagate via natural rebuilds.
 
* Policies and guidelines:
<!-- Do the packaging guidelines or other documents need to be updated for this feature?  If so, does it need to happen before or after the implementation is done?  If a FPC ticket exists, add a link here. Please submit a pull request with the proposed changes before submitting your Change proposal. -->
** Guidelines need to be modified ([https://pagure.io/packaging-committee/pull-request/1360 open Pull Request]).
 
* Trademark approval: N/A (not needed for this Change)
<!-- If your Change may require trademark approval (for example, if it is a new Spin), file a ticket ( https://pagure.io/Fedora-Council/tickets/issues ) requesting trademark approval from the Fedora Council. This approval will be done via the Council's consensus-based process. -->
 
* Alignment with Community Initiatives: N/A
<!-- Does your proposal align with the current Fedora Community Initiatives: https://docs.fedoraproject.org/en-US/project/initiatives/ ? It's okay if it doesn't, but it's something to consider -->
 
== Upgrade/compatibility impact ==
<!-- What happens to systems that have had a previous versions of Fedora installed and are updated to the version containing this change? Will anything require manual configuration or data migration? Will any existing functionality be no longer supported? -->
* For Java libraries:
** This change is removing `Requires` and therefore users manually installing a Java library will not additionally install the JVM.
 
* For Java applications:
** After fully implemented, applications will no longer be installable along with any JVM but rather only the system one (unless the package maintainer decides otherwise)
 
== How To Test ==
<!-- This does not need to be a full-fledged document. Describe the dimensions of tests that this change implementation is expected to pass when it is done.  If it needs to be tested with different hardware or software configurations, indicate them.  The more specific you can be, the better the community testing can be.
 
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* Installing a Java library should not typically install JVM (but can if the library depends on a Java application)
* Installing a Java application MUST cause the installation of the system-wide JVM (or a different version thereof)
* Executing a binary installed in typical locations (such as `/usr/bin`) MUST NOT cause an error related to the JVM not being installed.
 
== User Experience ==
<!-- If this change proposal is noticeable by users, how will their experiences change as a result?
 
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  - Packages are compressed more efficiently, making downloads and upgrades faster by 10%.
  - Kerberos tickets can be renewed automatically. Users will now have to authenticate less and become more productive. Credential management improvements mean a user can start their work day with a single sign on and not have to pause for reauthentication during their entire day.
- Libreoffice is one of the most commonly installed applications on Fedora and it is now available by default to help users "hit the ground running".
- Green has been scientifically proven to be the most relaxing color. The move to a default background color of green with green text will result in Fedora users being the most relaxed users of any operating system.
-->
Users with no Java application installed, but some Java libraries installed: the JVM may be automatically uninstalled as it is possibly not required by anything.
 
It is possible that there are users with only some older JVM installed. The following depends on the decision of each Java application package maintainer, but the general expectation is that the system-wide JVM will be installed and the older JVM will no longer be required by other packages.
 
Users who explicitly installed JVMs of various versions: no change.


== Scope/Policies and guidelines ==
== Scope/Trademark approval ==
== Scope/Objective alignment ==
== Upgrade & Compatibility impact ==
== How to test ==
== User experience ==
== Dependencies ==
== Dependencies ==
== Contingency plan ==
<!-- What other packages (RPMs) depend on this package?  Are there changes outside the developers' control on which completion of this change depends?  In other words, completion of another change owned by someone else and might cause you to not be able to finish on time or that you would need to coordinate?  Other upstream projects like the kernel (if this is not a kernel change)? -->
* `javapackages-tools`
** This change allows the removal of the `Requires` generator.
 
== Contingency Plan ==
<!-- If you cannot complete your feature by the final development freeze, what is the backup plan?  This might be as simple as "Revert the shipped configuration".  Or it might not (e.g. rebuilding a number of dependent packages).  If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy.  -->
* Contingency mechanism:  <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
** In case of unexpected problems, the `Requires` generators can be reintroduced into `javapackages-tools` and packages can be rebuilt.
 
<!-- When is the last time the contingency mechanism can be put in place?  This will typically be the beta freeze. -->
* Contingency deadline: Branch Fedora Linux 41 from Rawhide Tue 2024-08-06  <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
<!-- Does finishing this feature block the release, or can we ship with the feature in incomplete state? -->
* Blocks release? No <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
 
== Documentation ==
== Documentation ==
== Release notes ==
<!-- Is there upstream documentation on this change, or notes you have written yourself?  Link to that material here so other interested developers can get involved. -->
<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
No documentation outside of this document.
 
== Release Notes ==
<!-- The Fedora Release Notes inform end-users about what is new in the release.  Examples of past release notes are at https://docs.fedoraproject.org/en-US/fedora/latest/release-notes/ -->
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Latest revision as of 16:17, 8 May 2024


Drop Mandatory Requires on JRE

Important.png
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

Drop the requirement of Java libraries to have Requires on JREs.

Owner

Current status

Detailed Description

Current guidelines require all Java packages to Require: java-headless or java-headless >= 1:minimal_required_version.

Our aim is to drop this explicit requirement on Java library packages. The requirement should stay for Java applications.

Context

Java packages are compiled using javac into .class files and composed into .jar archives. Jar archives can be used as compile or runtime dependencies for other packages or can be directly executed with the java command provided by a JRE.

Jar archives can be executed using the command: java -jar ${FILE}. This command executes the main method either specified via CLI or specified within the Jar manifest file.

Java packages, which serve as libraries only, lack the main method and are not executable. Therefore, there is no requirement on any specific JRE imposed by the library implicitly.

Different JDKs

This proposal is also related to the topic of different JDKs. Developers may want to use or build packages which use a JDK different than the one provided by the java-<N>-openjdk package. After this proposal was implemented, they would be able to depend on Java library packages with no introduction of the OpenJDK package.

Rationale

Java libraries are more similar to native libraries than to libraries written in dynamic scripting languages. They are compiled to a bytecode and are not executable. Java libraries can be used as dependencies for any Java application and there is no implicit dependency on the system default JDK.

Java applications, on the other hand, are expected to be tested and to work with the system JDK and from the user's perspective: after installing an application they must be able to simply run the binary. Therefore the Requires on the system JDK is kept for Java applications.

Feedback

Benefit to Fedora

  • Very little user-visible benefit.
  • Reduced dependencies of Java packages.
  • Simplified maintenance of Java packages.
    • Smaller impact of JDK major updates (e.g. 1.8.0 -> 11 -> 17 -> 21). Introducing a new system version of JDK requires the rebuild of each Java package in order to have updated Requires to contain the newest version.

Scope

  • Proposal owners:
    • Find all Java applications in Fedora, i.e. packages which BuildRequire java-devel / maven-local / ant and at the same time install files into /bin or /sbin or /usr/bin or /usr/sbin.
    • Open pull requests adding Requires: java-headless into their .spec file.
    • Remove Requires generator from javapackages-tools
    • Wait for a mass rebuild.
  • Other developers:
    • Maintainers of Java applications will need to add an explicit Requires: java-headless field into their .spec file or a specific version of thereof (such as java-17-openjdk-headless).
  • Release engineering: #12069
    • Mass rebuild is not required, this change can propagate via natural rebuilds.
  • Trademark approval: N/A (not needed for this Change)
  • Alignment with Community Initiatives: N/A

Upgrade/compatibility impact

  • For Java libraries:
    • This change is removing Requires and therefore users manually installing a Java library will not additionally install the JVM.
  • For Java applications:
    • After fully implemented, applications will no longer be installable along with any JVM but rather only the system one (unless the package maintainer decides otherwise)

How To Test

  • Installing a Java library should not typically install JVM (but can if the library depends on a Java application)
  • Installing a Java application MUST cause the installation of the system-wide JVM (or a different version thereof)
  • Executing a binary installed in typical locations (such as /usr/bin) MUST NOT cause an error related to the JVM not being installed.

User Experience

Users with no Java application installed, but some Java libraries installed: the JVM may be automatically uninstalled as it is possibly not required by anything.

It is possible that there are users with only some older JVM installed. The following depends on the decision of each Java application package maintainer, but the general expectation is that the system-wide JVM will be installed and the older JVM will no longer be required by other packages.

Users who explicitly installed JVMs of various versions: no change.

Dependencies

  • javapackages-tools
    • This change allows the removal of the Requires generator.

Contingency Plan

  • Contingency mechanism:
    • In case of unexpected problems, the Requires generators can be reintroduced into javapackages-tools and packages can be rebuilt.
  • Contingency deadline: Branch Fedora Linux 41 from Rawhide Tue 2024-08-06
  • Blocks release? No

Documentation

No documentation outside of this document.

Release Notes

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