8283700: Add final or sealed modifier to appropriate java.awt API classes

[prrace]

JDK 17 delivered JEP 409: Sealed Classes : https://openjdk.java.net/jeps/409
In essence this JEP allows a class to limit which classes can subclass it.
If a class has no subclasses and cannot be subclassed outside the JDK it can also be made final.
Suitable classes across the JDK are being retro-fitted to be sealed (or made final) where it can be done compatibly.
This fix takes care of several AWT classes which were identified.
If later we need to remove sealed or make a class non-final that will also be a compatible change,
so we aren't locking ourselves into this.

All our automated regression tests - plus JCK tests have been run.

This will require a CSR

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed
• Change requires a CSR request to be approved

Issues

• JDK-8283700: Add final or sealed modifier to appropriate java.awt API classes
• JDK-8283813: Add final or sealed modifier to appropriate java.awt API classes (CSR)

Reviewers

• Joe Darcy (@jddarcy - Reviewer)
• Alexey Ivanov (@aivanov-jdk - Reviewer)
• Sergey Bylokhov (@mrserb - Reviewer)
• Prasanta Sadhukhan (@prsadhuk - Reviewer)

Reviewing

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Update a local copy of the PR:
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[prrace]

/csr

[bridgekeeper]

👋 Welcome back prr! 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]

@prrace has indicated that a compatibility and specification (CSR) request is needed for this pull request.
@prrace please create a CSR request for issue JDK-8283700. This pull request cannot be integrated until the CSR request is approved.

[openjdk]

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

• client

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[mlbridge]

Webrevs

• 00: Full (a71e9d9d)

[mrserb]

I wonder do we have some javac checks which may show some warnings related to these updated classes like not all subclasses are covered by the switch/unnecessary default branch/etc?

[forax]

@mrserb, you mean to detect that you can not add a new subclass without breaking the source backward compatibility.
You can add a test that switch over all the cases with no "default", if a new subclass is added, the test will not compile anymore.

[prrace]

I think Sergey is asking how javac identifies classes that are sub-classing the sealed class but not listed in the permits clause ?

[jddarcy]

I think Sergey is asking how javac identifies classes that are sub-classing the sealed class but not listed in the permits clause ?

If a sealed class does not have a permits clause, the allowed subclasses must be in the same file as the class in question, e.g. nested classes that were also subclasses or auxiliary classes. This is described in the JEP.

[mrserb]

Thank you for clarification

[prrace]

The CSR is now ready for review : https://bugs.openjdk.java.net/browse/JDK-8283813

[prsadhuk]

Suitable classes across the JDK are being retro-fitted to be sealed

How does this "suitability" check done? Are these exhaustive or more awt classes will be added?
Do we need to do the same for swing classes too?

[jddarcy]

Suitable classes across the JDK are being retro-fitted to be sealed

How does this "suitability" check done? Are these exhaustive or more awt classes will be added? Do we need to do the same for swing classes too?

I wrote an annotation processor to look for candidates to make sealed (public classes with no public or protected constructors and at least one package access constructor). Phil has filed bugs for swing (JDK-8283706) and other client areas.

[openjdk]

@prrace 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:

8283700: Add final or sealed modifier to appropriate java.awt API classes

Reviewed-by: darcy, aivanov, serb, psadhukhan

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 36 new commits pushed to the master branch:

• d066856: 8282162: [vector] Optimize integral vector negation API
• bfd9c2b: 8283015: Create a test for JDK-4715496
• 8cdabea: 8207025: JvmtiEnv::SetSystemProperty() does not handle OOM
• 272d653: 8283889: Fix Typo in open/src/java.sql/share/classes/java/sql/package-info.java
• a9a9b90: 8283723: Update Visual Studio 2022 to version 17.1.0 for Oracle builds on Windows
• 489b27d: 8282776: Bad NullPointerException message when invoking an interface MethodHandle on a null receiver
• 072f2c4: 8283782: Redundant verification of year in LocalDate::ofEpochDay
• 2fef5d4: 8281853: serviceability/sa/ClhsdbThreadContext.java failed with NullPointerException: Cannot invoke "sun.jvm.hotspot.gc.shared.GenCollectedHeap.getGen(int)" because "this.heap" is null
• f9f439a: 8283717: vmTestbase/nsk/jdi/ThreadStartEvent/thread/thread001 failed due to SocketTimeoutException
• 9591306: 8283772: Make sun.net.dns.ResolverConfiguration sealed
• ... and 26 more: https://git.openjdk.java.net/jdk/compare/c2c0cb2a4372d78658326461562363de9a1a194f...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.

[prrace]

/integrate

[openjdk]

Going to push as commit e85fa2f.
Since your change was applied there have been 53 commits pushed to the master branch:

• ec9ab55: 8282374: Java_sun_awt_X11_XlibWrapper_XSynchronize is wrong and unused
• a625bfd: 8283903: GetContainerCpuLoad does not return the correct result in share mode
• 97c7298: 8282046: Create a regression test for JDK-8000326
• ae57258: 8283715: Update ObjectStreamClass to be final
• d9d19e9: 8284015: ProblemList containers/docker/TestJcmd.java on linux-x64
• a3223cb: 8283999: Update JMH devkit to 1.35
• e8e9b8d: 8282926: AArch64: Optimize out WHILELO with PTRUE
• 720e751: 8283937: riscv: RVC: Fix c_beqz to c_bnez
• 51c05e8: 8282764: AArch64: compiler/vectorapi/reshape/TestVectorCastNeon.java failed with incorrect result
• b82b009: 8283737: riscv: MacroAssembler::stop() should emit fixed-length instruction sequence
• ... and 43 more: https://git.openjdk.java.net/jdk/compare/c2c0cb2a4372d78658326461562363de9a1a194f...master

Your commit was automatically rebased without conflicts.

[openjdk]

@prrace Pushed as commit e85fa2f.

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