CI: Use Java 26

[cstamas]

Up CI matrix from Java 25 to Java 26.

[cstamas]

@kwin this seems quite consistent: JDK transport UTs fail on Java 26?

[kwin]

Error:  Tests run: 85, Failures: 1, Errors: 0, Skipped: 6, Time elapsed: 4.443 s <<< FAILURE! -- in org.eclipse.aether.transport.jdk.JdkTransporterTest
Error:  org.eclipse.aether.transport.jdk.JdkTransporterTest.testRetryHandler_defaultCount_negative -- Time elapsed: 0.022 s <<< FAILURE!
org.opentest4j.AssertionFailedError: Expected error
	at org.junit.jupiter.api.AssertionUtils.fail(AssertionUtils.java:38)
	at org.junit.jupiter.api.Assertions.fail(Assertions.java:138)
	at org.eclipse.aether.transport.jdk.JdkTransporterTest.testRetryHandler_defaultCount_negative(JdkTransporterTest.java:90)
	at java.base/java.lang.reflect.Method.invoke(Method.java:565)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1612)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1612)

Seems some internal retry mechanism has changed in Java 26...

[kwin]

With Java 26 the num of internal retries is 5 times the number of retries controlled via Methanol (=3 by default). Prior Java 26 the internal number of retries was 2... The retry handling got changed in openjdk/jdk@e8db14f#diff-41e3c3f66a6d78612e230f2546ac15e3f82619efe333a731b64f59a9e4991816R613.

[kwin]

Please rebase on top of master now @cstamas.

[kwin]

Ok, still not working reliably, I would tend to disable the ITs related to retries in JDKTransporter as those are too brittle. WDYT @cstamas ?

[cstamas]

Yup, go for it.

[gnodet]

AI Review — PR #1912: CI: Use Java 26

Hi @cstamas, thanks for keeping CI up to date with the latest JDK!

⚠️ JDK 26 CI jobs are red (medium)

All 6 JDK 26 jobs (ubuntu/windows/macos × Maven 3.9.16/4.0.0-rc-5) are currently failing. The failure is in JdkTransporterTest.testRetryHandler_defaultCount_negative, caused by changed HTTP client retry semantics in Java 26.

A partial fix was merged to master on July 2 ("Limit internal retries to 1 with Java 26+") but @kwin reported on July 8 that it's "still not working reliably" and proposed disabling the brittle retry ITs. You agreed with that approach.

The PR branch appears to be 66 commits behind master and would need:

1. A rebase onto current master
2. The agreed-upon retry IT disabling (which hasn't been pushed yet)

Once both are done, CI should go green and this can merge.

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🤖 This review was generated by ForgeBot using a maker/checker pattern (reviewer + independent verifier). All findings were independently confirmed.

[gnodet]

Review Summary

The one-line JDK matrix bump from 25 to 26 is the right thing to do, @cstamas, but there are two blockers before this can merge:

CI Failures (confirmed)

All 6 JDK-26 CI matrix entries (ubuntu/windows/macos × Maven 3.9.16/4.0.0-rc-5) are failing. The failure is in JdkTransporterTest.testRetryHandler_defaultCount_negative due to changed HTTP client retry semantics in Java 26 (jdk.httpclient.redirects.retrylimit).

As @kwin identified, the partial fix merged to master (commit f9d2c83) is "still not working reliably." The agreed-upon path forward — disabling the brittle retry ITs — has not yet been applied to this branch.

Branch State (confirmed)

The branch is 8 commits behind master and contains a merge commit (bbd74e75). A rebase is needed both to incorporate the existing retry fixes on master and to align with the project's squash/rebase merge policy. @kwin also requested this in the PR comments.

Suggested Path Forward

1. Rebase onto current master to pick up the partial retry fix
2. Push an additional commit that @Disabled-annotates the brittle testRetryHandler_defaultCount_negative test (and any related retry ITs that remain flaky under Java 26)
3. Verify CI goes green, then merge

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This review was generated by an AI agent and may contain inaccuracies. Please verify all suggestions before applying.

Claude Code on behalf of Guillaume Nodet