[jdk21u-dev] RFR: 8342905: Thread.setContextClassloader from thread in FJP commonPool task no longer works after JDK-8327501 redux

[Martin Balao]

On Mon, 2 Dec 2024 20:20:54 GMT, Francisco Ferrari Bihurriet <fferrari at openjdk.org> wrote:

> Hi,
> 
> I would like to propose a [JDK-8342905](https://bugs.openjdk.org/browse/JDK-8342905 "Thread.setContextClassloader from thread in FJP commonPool task no longer works after JDK-8327501 redux") (openjdk/jdk23u at 872ae1347198408ffd62559ca8c1a7420c4a8108) backport from 23u to 21u.
> 
> The backport is not clean, for the following reasons:
> 
> * The `jdk.internal.access.JavaLangAccess` import context in `ForkJoinPool.java` has changed from 21u to 23u, due to [JDK-8288899](https://bugs.openjdk.org/browse/JDK-8288899 "java/util/concurrent/ExecutorService/CloseTest.java failed with "InterruptedException: sleep interrupted"") (openjdk/jdk at 667cca9d7aef1ff4abe630cefaac34c0b1646925)
> * The `jdk.internal.access.JavaLangAccess::allowSecurityManager` method didn't exist in 21u, so I picked it from [JDK-8296244](https://bugs.openjdk.org/browse/JDK-8296244 "Alternate implementation of user-based authorization Subject APIs that doesn’t depend on Security Manager APIs") (openjdk/jdk at d32746ef4a0ce6fec558274244321991be141698)
>     * We don't need [JDK-8296244](https://bugs.openjdk.org/browse/JDK-8296244 "Alternate implementation of user-based authorization Subject APIs that doesn’t depend on Security Manager APIs"), just the access to the `System::allowSecurityManager` private method
>     * I don't see [JDK-8296244](https://bugs.openjdk.org/browse/JDK-8296244 "Alternate implementation of user-based authorization Subject APIs that doesn’t depend on Security Manager APIs") as a possible dependency candidate, given it is a much broader change with its own CSR affecting the Java SE API and only approved for 23
> 
> This pull request depends on @martinuy's #1181.
> 
> #### Testing
> 
> As part of our testing, we observed all the tests pass in the following categories:
> 
> * `jdk:tier1` (see [GitHub Actions run](https://github.com/franferrax/jdk21u-dev/actions/runs/12126257318))
> * `jdk/java/util/concurrent/forkjoin`
> * `jdk/java/util/concurrent/tck`
> 
> Additionally, an internal test for [JDK-8237117](https://bugs.openjdk.org/browse/JDK-8237117 "Better ForkJoinPool behavior") was executed without issues.

The proposed backport looks good to me. I agree with not considering JDK-8296244 a dependency.

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Marked as reviewed by mbalao (Reviewer).

PR Review: https://git.openjdk.org/jdk21u-dev/pull/1192#pullrequestreview-2474001184