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7357: Double-Checked Locking in Agent Plugin code #282

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7357: Double-Checked Locking in Agent Plugin code #282

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guruhb
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@guruhb guruhb commented Jul 26, 2021 •
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Trivial Fortify warning fix

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  • Commit message must refer to an issue
  • Change must be properly reviewed

Issue

  • JMC-7357: Double-Checked Locking in Agent Plugin code

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bridgekeeper bot commented Jul 26, 2021

👋 Welcome back ghb! 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 openjdk bot added the rfr label Jul 26, 2021
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mlbridge bot commented Jul 26, 2021 •
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Webrevs

jpbempel
jpbempel reviewed Jul 26, 2021
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...agent/src/main/java/org/openjdk/jmc/console/agent/manager/model/PresetRepositoryFactory.java Outdated
if (singleton == null) {
singleton = create();
}
singleton = create();
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Actually, singleton field need also to be volatile.
see https://shipilev.net/blog/2014/safe-public-construction/ for more info

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@thegreystone thegreystone Jul 26, 2021 •
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Indeed. I haven't checked, but couldn't all this be avoided by simply creating the singleton at the field declaration - does it really have to be lazily created?

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We could have created a Singleton in field declaration if below points were true :

  1. If we had only "PresetRepository" as a main class with Singleton (Currently this is a factory).
  2. Likelihood of "PresetRepository" object required all the time of JMC's lifecycle .
  • "- does it really have to be lazily created?"
  1. Singleton Object + init (PresetRepository.addLocalPresetTo(...) ) is doing a File Operation.

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Actually, singleton field need also to be volatile.
see https://shipilev.net/blog/2014/safe-public-construction/ for more info

Thanks @jpbempel that was an informative article and added volatile to the field declaration, with this neither Fortify nor apptest complained.

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openjdk bot commented Jul 26, 2021 •
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@guruhb 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:

7357: Double-Checked Locking in Agent Plugin code

Reviewed-by: jpbempel, hirt

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 17 new commits pushed to the master branch:

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 openjdk bot added the ready label Jul 26, 2021
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Please open up the Jira issue (JMC-7357).

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guruhb commented Jul 30, 2021

Please open up the Jira issue (JMC-7357).

Please check now!

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guruhb commented Jul 30, 2021

/integrate

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openjdk bot commented Jul 30, 2021

Going to push as commit 70901a3.
Since your change was applied there have been 17 commits pushed to the master branch:

Your commit was automatically rebased without conflicts.

@openjdk openjdk bot closed this Jul 30, 2021
@openjdk openjdk bot added integrated and removed ready rfr labels Jul 30, 2021
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openjdk bot commented Jul 30, 2021

@guruhb Pushed as commit 70901a3.

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

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@thegreystone thegreystone thegreystone approved these changes

@jpbempel jpbempel jpbempel approved these changes

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@guruhb @thegreystone @jpbempel