8372048: Performance improvement on Linux remote desktop

[Renjithkannath]

Hi Reviewers,

Observed these two demon threads are created on class initializing time due to static variable and static block call. Observed ScreencastHelper.isAvailable() from XToolkit.java call is enough to start these demon threads on latest Linux (Gnome version 47 and above). In my observation some simple workflows not passing through the code where these Watchers are required, at the same time threads are running because of the above reason. So moving those into lazy loading will improve loading time and performance.

Please review and let me know your suggestions.

Renjith.

---

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

Issue

• JDK-8372048: Performance improvement on Linux remote desktop (Enhancement - P4)

Reviewers

• Alexander Zvegintsev (@azvegint - Reviewer)
• Sergey Bylokhov (@mrserb - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/28369/head:pull/28369
$ git checkout pull/28369

Update a local copy of the PR:
$ git checkout pull/28369
$ git pull https://git.openjdk.org/jdk.git pull/28369/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 28369

View PR using the GUI difftool:
$ git pr show -t 28369

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/28369.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back rkannathpari! 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]

@Renjithkannath 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:

8372048: Performance improvement on Linux remote desktop

Reviewed-by: azvegint, serb

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 26 new commits pushed to the master branch:

• 99135d2: 8359145: Implement JEP 530: Primitive Types in Patterns, instanceof, and switch (Fourth Preview)
• 02ff38f: 8363986: Heap region in CDS archive is not at deterministic address
• 902aa4d: 8372120: Add missing sound keyword to MIDI tests
• ... and 23 more: https://git.openjdk.org/jdk/compare/8af594371979b2b76ec04e0a2753413dc35b8d44...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.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@azvegint, @mrserb) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[openjdk]

@Renjithkannath The following label will be automatically applied to this pull request:

• client

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 00: Full (c290886b)

[gredler]

I'm not familiar with this part of the code, but this might be a good candidate for StableValue / LazyConstant, once it's ready? https://mail.openjdk.org/pipermail/client-libs-dev/2025-September/032518.html

[Renjithkannath]

/integrate

[openjdk]

@Renjithkannath
Your change (at version c290886) is now ready to be sponsored by a Committer.

[azvegint]

/sponsor

[openjdk]

Going to push as commit 0b3df48.
Since your change was applied there have been 28 commits pushed to the master branch:

• d2926df: 8371649: ZGC: AArch64: redundant OrderAccess::fence in ZBarrierSetAssembler::patch_barrier_relocation
• 54893dc: 8371985: Parallel: Move should_attempt_scavenge to ParallelScavengeHeap
• 99135d2: 8359145: Implement JEP 530: Primitive Types in Patterns, instanceof, and switch (Fourth Preview)
• ... and 25 more: https://git.openjdk.org/jdk/compare/8af594371979b2b76ec04e0a2753413dc35b8d44...master

Your commit was automatically rebased without conflicts.

[openjdk]

@azvegint @Renjithkannath Pushed as commit 0b3df48.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.