8368500: ContextClassLoader cannot be reset on threads in ForkJoinPool.commonPool()

[rm-gh-8]

Backporting JDK-8368500: ContextClassLoader cannot be reset on threads in ForkJoinPool.commonPool()

For parity with Oracle JDK.

With the Security Manager permanently disabled in JDK 24, setCCL allows setting a custom context class loader but prevents resetting it back to the system class loader before executing subsequent task code. This change relaxes the restriction to allow resetting to the system class loader.

Ran GHA Sanity Checks (passed), jtreg tier1 tests (passed) and related tests (passed) on linux-x64, linux-aarch64, macos-aarch64 and windows-x64:

(Passed) - make test-tier1
(Passed) - make test TEST=test/jdk/java/util/concurrent/forkjoin/ContextClassLoaderTest.java

Results are attached.

linux-aarch64-jtreg-tier1.log
linux-aarch64-specific-test.log
linux-x64-jtreg-tier1.log
linux-x64-specific-test.log
macos-aarch64-jtreg-tier1.log
macos-aarch64-specific-test.log
windows-x64-jtreg-tier1.log
windows-x64-specific-test.log

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8368500 needs maintainer approval

Issue

• JDK-8368500: ContextClassLoader cannot be reset on threads in ForkJoinPool.commonPool() (Bug - P4 - Requested)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk25u-dev.git pull/65/head:pull/65
$ git checkout pull/65

Update a local copy of the PR:
$ git checkout pull/65
$ git pull https://git.openjdk.org/jdk25u-dev.git pull/65/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 65

View PR using the GUI difftool:
$ git pr show -t 65

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk25u-dev/pull/65.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back rm-gh-8! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[openjdk]

⚠️ @rm-gh-8 This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[rm-gh-8]

/approval request for backport of JDK-8368500: ContextClassLoader cannot be reset on threads in ForkJoinPool.commonPool().

For parity with Oracle JDK.

[openjdk]

@rm-gh-8
8368500: The approval request has been created successfully.

[mlbridge]

Webrevs

• 00: Full (a38407f6)

[rm-gh-8]

/approval request for backport of JDK-8368500: ContextClassLoader cannot be reset on threads in ForkJoinPool.commonPool().

For parity with Oracle JDK.

[openjdk]

@rm-gh-8
8368500: The approval request was already up to date.