8300866: Declare some classes final in java.io

[minborg]

This PR proposes declaring some internal classes in java.io as final, explicitly indicating that they are not intended for sub-classing.

If you think declaring classes final is just "static noice", please see http://minborgsjavapot.blogspot.com/2021/12/why-general-inheritance-is-flawed-and.html first and then come back and comment on the issue.

---

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-8300866: Declare some classes final in java.io

Reviewers

• Alan Bateman (@AlanBateman - Reviewer) ⚠️ Review applies to a77aa151

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk pull/12141/head:pull/12141
$ git checkout pull/12141

Update a local copy of the PR:
$ git checkout pull/12141
$ git pull https://git.openjdk.org/jdk pull/12141/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 12141

View PR using the GUI difftool:
$ git pr show -t 12141

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/12141.diff

[bridgekeeper]

👋 Welcome back pminborg! 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]

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

• core-libs

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[mlbridge]

Webrevs

• 01: Full (82a1c10e)
• 00: Full (a77aa151)

[AlanBateman]

Look okay. We should probably think about removing ExpiringCache as it hasn't been used for many releases.

[minborg]

Look okay. We should probably think about removing ExpiringCache as it hasn't been used for many releases.

It looks like CE is used in UnixFileSystem via the system property "sun.io.useCanonCaches" ?

[minborg]

/integrate

[openjdk]

@minborg this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout javaio_final_classes
git fetch https://git.openjdk.org/jdk master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

[AlanBateman]

It looks like CE is used in UnixFileSystem via the system property "sun.io.useCanonCaches" ?

It was disabled in JDK 12 and the general plan was to eventually remove it eventually.

[openjdk]

@minborg This pull request has not yet been marked as ready for integration.

[openjdk]

@minborg 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:

8300866: Declare some classes final in java.io

Reviewed-by: alanb

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 no new commits pushed to the master branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential 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.

[minborg]

/integrate

[openjdk]

Going to push as commit d117350.

[openjdk]

@minborg Pushed as commit d117350.

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