8371748: Remove the (empty) ThreadPoolExecutor.finalize() method

[bchristi-git]

From the bug report:
Prior to JDK 11, ThreadPoolExecutor.finalize() was specified to
"[invoke] shutdown() when this executor is no longer referenced and it has no threads."

In JDK 11, ThreadPoolExecutor.finalize() was re-specified to do nothing, leaving the finalize() method empty. (JDK-8190324).

In JDK 18, finalize() was deprecated for removal (JDK-8276447), after first being "standard" deprecated in JDK 9 (JDK-8165641).

The finalize() method can safely be removed from ThreadPoolExecutor.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change requires CSR request JDK-8371856 to be approved

Issues

• JDK-8371748: Remove the (empty) ThreadPoolExecutor.finalize() method (Bug - P4)
• JDK-8371856: Remove the (empty) ThreadPoolExecutor.finalize() method (CSR)

Reviewers

• Viktor Klang (@viktorklang-ora - Reviewer)
• Jaikiran Pai (@jaikiran - Reviewer)
• Alan Bateman (@AlanBateman - Reviewer)

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[bchristi-git]

/csr

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[openjdk]

@bchristi-git This change now passes all automated pre-integration checks.

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

8371748: Remove the (empty) ThreadPoolExecutor.finalize() method

Reviewed-by: vklang, jpai, alanb

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At the time when this comment was updated there had been 238 new commits pushed to the master branch:

• c55287d: 8370890: Start of release updates for JDK 27
• 45dcc0e: 8371914: PNG defines in CFLAGS can cause compilation errors with external libpng
• 2735140: 8370939: C2: SIGSEGV in SafePointNode::verify_input when processing MH call from Compile::process_late_inline_calls_no_inline()
• ... and 235 more: https://git.openjdk.org/jdk/compare/41d6dc3a15fd3041aaee7b9b7f7980ede5f7940d...master

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[mlbridge]

Webrevs

• 01: Full - Incremental (1984cd4d)
• 00: Full (f166b51a)

[viktorklang-ora]

Thanks @bchristi-git!

[jaikiran]

The failures in the GitHub actions job appear related:

/home/runner/work/jdk/jdk/test/jdk/java/util/concurrent/tck/ThreadPoolExecutorSubclassTest.java:2011: error: unreported exception Throwable; must be caught or declared to be thrown
                super.finalize();
                              ^

[bchristi-git]

The failures in the GitHub actions job appear related:

/home/runner/work/jdk/jdk/test/jdk/java/util/concurrent/tck/ThreadPoolExecutorSubclassTest.java:2011: error: unreported exception Throwable; must be caught or declared to be thrown
                super.finalize();
                              ^

Indeed.
My understanding is that that is being handled by JDK-8371682.

[bchristi-git]

Thank you, reviewers. :)
Can I also get a review on the CSR? TIA.

[AlanBateman]

Indeed. My understanding is that that is being handled by JDK-8371682.

It might make more sense for this PR to remove testFinalizeMethodCallsSuperFinalize as it's part of the removal.

[sendaoYan]

Indeed. My understanding is that that is being handled by JDK-8371682.

It might make more sense for this PR to remove testFinalizeMethodCallsSuperFinalize as it's part of the removal.

Should I close #28278 as duplicated to this PR.

[ExE-Boss]

Wrt. the CSR’s “Compatibility Risk Description”:

Subclasses that @⁠Override finalize, call super.finalize() or call finalize() directly will continue to compile and execute.

This isn’t completely correct, as super.finalize() will now have throws Throwable, where it previously didn’t, causing a source incompatibility, as seen in ThreadPoolExecutorSubclassTest:

/home/runner/work/jdk/jdk/test/jdk/java/util/concurrent/tck/ThreadPoolExecutorSubclassTest.java:2011:
error: unreported exception Throwable; must be caught or declared to be thrown
                super.finalize();
                              ^

[AlanBateman]

super.finalize() will now have throws Throwable, where it previously didn’t, causing a source incompatibility, as seen in ThreadPoolExecutorSubclassTest:

Indeed, there is a source compatibility issue here. @bchristi-git Have you done corpus searches yet to see if there are cases that extend TPE and invoke super.finalize? It wouldn't be in code written in recent years, but maybe older code that needs updating. The overall risk here is low though and the migration would be to just drop the super.finalize() as it doesn't do anything since JDK 11.

[sendaoYan]

@bchristi-git I have integrated #28278, I think you should merge the master to fix the GHA test failures.

[bchristi-git]

@bchristi-git Have you done corpus searches yet to see if there are cases that extend TPE and invoke super.finalize?

My Corpus searches found quite a few TPE subclasses, but none of them override finalize or invoke finalize.

[bchristi-git]

I've created a Release Note for this change, if someone could have a look and review it:
https://bugs.openjdk.org/browse/JDK-8373057
TIA

[jaikiran]

Hello Brent, the release note looks good to me. Just a minor suggestion, perhaps the following:

With the removal of ThreadPoolExecutor.finalize(), existing code that subclasses ThreadPoolExecutor ...

could be replaced with

With the removal of ThreadPoolExecutor.finalize(), any existing class that extends ThreadPoolExecutor ...

[bchristi-git]

Thanks, Jai - RN updated.

[bchristi-git]

/integrate

[openjdk]

Going to push as commit f3dd8da.
Since your change was applied there have been 255 commits pushed to the master branch:

• 4378789: 8373145: [BACKOUT] Remove ThreadLocalAllocBuffer::_reserve_for_allocation_prefetch
• a20b7eb: 8373125: Add defensive screening of modifiers for Field and Parameter toString() results
• 520c092: 8362658: sun/security/ssl/SSLEngineImpl/* tests duplicate jvm flags
• ... and 252 more: https://git.openjdk.org/jdk/compare/41d6dc3a15fd3041aaee7b9b7f7980ede5f7940d...master

Your commit was automatically rebased without conflicts.

[openjdk]

@bchristi-git Pushed as commit f3dd8da.

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