8328366: Thread.setContextClassloader from thread in FJP commonPool task no longer works after JDK-8327501

[viktorklang-ora]

This is a draft PR with a potential solution to 8328366 without regressing 8327501.

@DougLea To avoid regressions in the future, where would regression tests for this ideally be located?

---

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Issue

• JDK-8328366: Thread.setContextClassloader from thread in FJP commonPool task no longer works after JDK-8327501 (Bug - P3)

Reviewers

• Mandy Chung (@mlchung - Reviewer)
• Alan Bateman (@AlanBateman - Reviewer)

Reviewing

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[openjdk]

@viktorklang-ora This change now passes all automated pre-integration checks.

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After integration, the commit message for the final commit will be:

8328366: Thread.setContextClassloader from thread in FJP commonPool task no longer works after JDK-8327501

Reviewed-by: mchung, alanb

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At the time when this comment was updated there had been 223 new commits pushed to the master branch:

• 4276d5c: 8329637: Apparent typo in java.security file property jdk.tls.keyLimits
• 6382a12: 8326666: Remove the Java Management Extension (JMX) Subject Delegation feature
• d90e5b5: 8329546: Assume sized integral types are available
• f3db279: 8327410: Add hostname option for UL file names
• 21867c9: 8313332: Simplify lazy jmethodID cache in InstanceKlass
• b9da140: 8329594: G1: Consistent Titles to Thread Work Items.
• a169c06: 8329580: Parallel: Remove VerifyObjectStartArray
• 8efd7aa: 8328786: [AIX] move some important warnings/errors from trcVerbose to UL
• f26e430: 8327110: Refactor create_bool_from_template_assertion_predicate() to separate class and fix identical cloning cases used for Loop Unswitching and Split If
• e5e21a8: 8328702: C2: Crash during parsing because sub type check is not folded
• ... and 213 more: https://git.openjdk.org/jdk/compare/f1c69ccadb83306d1bb4860ff460a253af99643c...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

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[viktorklang-ora]

@DougLea @AlanBateman Added a regression test to ForkJoinPool9Test. I think this is the fix we need. Please review.

[mlbridge]

Webrevs

• 00: Full (2481cfa9)

[jerboaa]

Is there any update on this PR?

[jerboaa]

FWIW, I've tested this with the quarkus reproducer and a reproducer for the class load leak. They seem both to work with this patch.

Please be sure to mention the bug for the ThreadLocal follow-up. Thanks!

[AlanBateman]

The change looks okay. It's unfortunate we didn't catch this but you've added a test. As a general point, I hope these tasks that are running in the common pool (or any thread pool for that matter) are resetting the TCCL before they complete.

[viktorklang-ora]

Follow-up issue regarding the clearing of the Thread Locals here: https://bugs.openjdk.org/browse/JDK-8329701

[viktorklang-ora]

/integrate

[openjdk]

Going to push as commit 28216aa.
Since your change was applied there have been 223 commits pushed to the master branch:

• 4276d5c: 8329637: Apparent typo in java.security file property jdk.tls.keyLimits
• 6382a12: 8326666: Remove the Java Management Extension (JMX) Subject Delegation feature
• d90e5b5: 8329546: Assume sized integral types are available
• f3db279: 8327410: Add hostname option for UL file names
• 21867c9: 8313332: Simplify lazy jmethodID cache in InstanceKlass
• b9da140: 8329594: G1: Consistent Titles to Thread Work Items.
• a169c06: 8329580: Parallel: Remove VerifyObjectStartArray
• 8efd7aa: 8328786: [AIX] move some important warnings/errors from trcVerbose to UL
• f26e430: 8327110: Refactor create_bool_from_template_assertion_predicate() to separate class and fix identical cloning cases used for Loop Unswitching and Split If
• e5e21a8: 8328702: C2: Crash during parsing because sub type check is not folded
• ... and 213 more: https://git.openjdk.org/jdk/compare/f1c69ccadb83306d1bb4860ff460a253af99643c...master

Your commit was automatically rebased without conflicts.

[openjdk]

@viktorklang-ora Pushed as commit 28216aa.

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