GH-43378: [Java][CI] Don't configure multithreading when building javadocs

[danepitkin]

Rationale for this change

Apparently some maven plugins are not thread safe and started throwing errors in the test-debian-12-docs CI job when building javadocs.

What changes are included in this PR?

• Remove multithreading config when building javadocs

Are these changes tested?

CI

Are there any user-facing changes?

No

• GitHub Issue: [Java][CI] AMD64 Debian 12 Complete Documentation CI Failure #43378

[github-actions]

Thanks for opening a pull request!

If this is not a minor PR. Could you open an issue for this pull request on GitHub? https://github.com/apache/arrow/issues/new/choose

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See also:

• Other pull requests
• Contribution Guidelines - Contributing Overview

[danepitkin]

@github-actions crossbow submit test-debian-12-docs

[github-actions]

Revision: e06d43e

Submitted crossbow builds: ursacomputing/crossbow @ actions-660dc2a81f

Task	Status
test-debian-12-docs

[danepitkin]

@github-actions crossbow submit test-debian-12-docs

[github-actions]

Revision: 564a719

Submitted crossbow builds: ursacomputing/crossbow @ actions-d4dc0f1198

Task	Status
test-debian-12-docs

[danepitkin]

@github-actions crossbow submit test-debian-12-docs

[github-actions]

Revision: e5f4a77

Submitted crossbow builds: ursacomputing/crossbow @ actions-0c1dbe8a7e

Task	Status
test-debian-12-docs

[danepitkin]

@github-actions crossbow submit test-debian-12-docs

[github-actions]

Revision: 5c0bfc6

Submitted crossbow builds: ursacomputing/crossbow @ actions-10ce915a60

Task	Status
test-debian-12-docs

[danepitkin]

@github-actions crossbow submit test-debian-12-docs

[github-actions]

Revision: 9fd0026

Submitted crossbow builds: ursacomputing/crossbow @ actions-8f7698b5c5

Task	Status
test-debian-12-docs

[github-actions]

⚠️ GitHub issue #43378 has been automatically assigned in GitHub to PR creator.

[danepitkin]

@github-actions crossbow submit test-debian-12-docs

[github-actions]

Revision: 9fd0026

Submitted crossbow builds: ursacomputing/crossbow @ actions-08d166e83d

Task	Status
test-debian-12-docs

[danepitkin]

@github-actions crossbow submit test-debian-12-docs

[github-actions]

Revision: ac61ffd

Submitted crossbow builds: ursacomputing/crossbow @ actions-dd7303454f

Task	Status
test-debian-12-docs

[danepitkin]

@github-actions crossbow submit test-debian-12-docs

[github-actions]

Revision: f3b7611

Submitted crossbow builds: ursacomputing/crossbow @ actions-74133f613d

Task	Status
test-debian-12-docs

[kou]

+1

Great!

[vibhatha]

Thanks @danepitkin for fixing this.

[laurentgo]

maven-site-plugin is supposedly thread-safe according to https://issues.apache.org/jira/browse/MSITE-873. Should we report the issue upstream?

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 4 benchmarking runs that have been run so far on merge-commit fc80d7d.

There were no benchmark performance regressions. 🎉

The full Conbench report has more details. It also includes information about 2 possible false positives for unstable benchmarks that are known to sometimes produce them.

[danepitkin]

maven-site-plugin is supposedly thread-safe according to https://issues.apache.org/jira/browse/MSITE-873. Should we report the issue upstream?

Good point. Should we first try upgrading to latest first? We are using maven-site-plugin v3.12.1 (defined in the parent apache pom I believe), but latest is v4.0.0-M9.

[danepitkin]

I'm also not able to reproduce it locally on a different platform (macos). I wonder if it could be that we have an incompatible version matrix configured between the different maven plugins that specifically plagues our CI?

[danepitkin]

Actually, I do see this warning from this CI job when trying to reenable multithreading.

Warning:  *****************************************************************
Warning:  * Your build is requesting parallel execution, but this         *
Warning:  * project contains the following plugin(s) that have goals not  *
Warning:  * marked as thread-safe to support parallel execution.          *
Warning:  * While this /may/ work fine, please look for plugin updates    *
Warning:  * and/or request plugins be made thread-safe.                   *
Warning:  * If reporting an issue, report it against the plugin in        *
Warning:  * question, not against Apache Maven.                           *
Warning:  *****************************************************************
Warning:  The following plugins are not marked as thread-safe in Arrow Bill of Materials:
Warning:    org.apache.maven.plugins:maven-site-plugin:3.12.1
Warning:  
Warning:  Enable debug to see precisely which goals are not marked as thread-safe.
Warning:  *****************************************************************

https://github.com/ursacomputing/crossbow/actions/runs/10394740527/job/28785211517

[danepitkin]

According to the Jira ticket (https://issues.apache.org/jira/browse/MSITE-873) this was fixed in 3.20+. We just need to upgrade if we want to use multithreading. The best approach is probably to use a later apache parent pom, which does use a later version.