8338939: Simplify processing of hidden class names

[shipilev]

Makes JFR more durable by avoiding Java mirror accesses for the classes that might be unloading. We were seeing the problems (crashes) at least with Shenandoah in both mainline and JDK 21u. There seem to be no bugtail for this change since JDK 24 integration 11 months ago.

Additional testing:

• Linux AArch64 server fastdebug, jdk/jfr
• Linux AArch64 server fastdebug, jdk/jfr + -XX:+UseShenandoahGC

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8338939 needs maintainer approval

Issue

• JDK-8338939: Simplify processing of hidden class names (Enhancement - P3 - Approved)

Reviewing

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Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk21u-dev.git pull/2018/head:pull/2018
$ git checkout pull/2018

Update a local copy of the PR:
$ git checkout pull/2018
$ git pull https://git.openjdk.org/jdk21u-dev.git pull/2018/head

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Checkout this PR locally:
$ git pr checkout 2018

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$ git pr show -t 2018

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https://git.openjdk.org/jdk21u-dev/pull/2018.diff

Using Webrev

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[bridgekeeper]

👋 Welcome back shade! 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]

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

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

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

8338939: Simplify processing of hidden class names

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 14 new commits pushed to the master branch:

• d0f905c: 8350665: SIZE_FORMAT_HEX macro undefined in gtest
• 2ae23bd: 8310264: In PhaseChaitin::Split defs and phis are leaked
• aab1e21: 8358452: JNI exception pending in Java_sun_awt_screencast_ScreencastHelper_remoteDesktopKeyImpl of screencast_pipewire.c:1214 (ID: 51119)
• ... and 11 more: https://git.openjdk.org/jdk21u-dev/compare/3daec2546c499ffd92891d2c276bca21c038ed21...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.

[openjdk]

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

[openjdk]

⚠️ @shipilev 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.

[mlbridge]

Webrevs

• 01: Full (c71add0c)
• 00: Full (d71e1a0f)

[shipilev]

GHA failures are environmental and related to openjdk/jdk#26447.

[shipilev]

/approval request Makes JFR more durable by avoiding Java mirror accesses for the classes that might be unloading. We were seeing the problems (crashes) at least with Shenandoah in both mainline and JDK 21u. Applies cleanly. JFR tests are passing. The risk is medium: the change is contained in JFR, pretty well isolated, no bugtail since this change since JDK 24 integration 11 months ago.

[openjdk]

@shipilev
8338939: The approval request has been created successfully.

[shipilev]

@mgronlun @egahlin, sanity checking: Do you see any problems with this patch going into JDK 21u?

[shipilev]

Force-pushed to get the GHA cross-compilation fixes. Otherwise the backport is the same.

[shipilev]

@mgronlun @egahlin, sanity checking: Do you see any problems with this patch going into JDK 21u?

Friendly reminder.

[openjdk]

@shipilev Please do not rebase or force-push to an active PR as it invalidates existing review comments. Note for future reference, the bots always squash all changes into a single commit automatically as part of the integration. See OpenJDK Developers’ Guide for more information.