8344841: ClassPrinter prints confusing value for null

[asotona]

ClassPrinter prints null values as String "null" or as String.valueOf(ConstantDescs.BSM_NULL_CONSTANT), based on context.

This patch unifies handling of null values.
They are now exclusively represented as ConstantDescs.BSM_NULL_CONSTANT.
In Json and Yaml format is null value printed unquoted and in Xml as <null/>.
In Json and Yaml is "null" String printed quoted to distinguish from the null value.

Please review.

Thank you,
Adam

---

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Issue

• JDK-8344841: ClassPrinter prints confusing value for null (Bug - P4)

Reviewers

• Chen Liang (@liach - Reviewer)

Reviewing

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[bridgekeeper]

👋 Welcome back asotona! 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]

@asotona 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:

8344841: ClassPrinter prints confusing value for null

Reviewed-by: liach

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 40 new commits pushed to the master branch:

• ddc8a9d: 8344366: Remove Security Manager dependencies from javax.net.ssl and sun.security.ssl packages
• 965aace: 8335468: [XWayland] JavaFX hangs when calling java.awt.Robot.getPixelColor
• 811d08c: 8340010: Fix vectorization tests with compact headers
• 519bb26: 8344217: Remove calls to SecurityManager and doPrivileged in java.net.DatagramSocket and java.net.NetMulticastSocket after JEP 486 integration
• d112f35: 8344855: Remove calls to SecurityManager and doPrivileged in HTTP related implementation classes in the sun.net and sun.net.www.http packages after JEP 486 integration
• da4b7a8: 8341436: containers/docker/TestJcmdWithSideCar.java takes needlessly long to run
• 333a997: 8335231: [macos] Test java/awt/print/PrinterJob/Cancel/PrinterJobCancel.java failed on macOS because the case didn't get the expected PrintAbortException
• 9576546: 8343698: Linux x86_64 lto build gives a lot of warnings and fails lto-wrapper: fatal error: make returned 2 exit status
• 68ba7ee: 8340205: Native linker allows MemoryLayout consisting of only PaddingLayout
• 6f622da: 8344923: Problem list on java/awt/Robot/ScreenCaptureRobotTest.java on macOS
• ... and 30 more: https://git.openjdk.org/jdk/compare/50c099d69e9cef5c38a2624d7c798360eb6c1fba...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]

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

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[mlbridge]

Webrevs

• 01: Full - Incremental (17749f83)
• 00: Full (6db7e46e)

[liach]

Suggested change

	.map((Function<Utf8Entry, ConstantDesc>)Utf8Entry::stringValue).orElse(BSM_NULL_CONSTANT),
	.<ConstantDesc>map(Utf8Entry::stringValue).orElse(BSM_NULL_CONSTANT),

same for other casts.

[asotona]

Thank you for the review!

/integrate

[openjdk]

Going to push as commit c6b14c6.
Since your change was applied there have been 40 commits pushed to the master branch:

• ddc8a9d: 8344366: Remove Security Manager dependencies from javax.net.ssl and sun.security.ssl packages
• 965aace: 8335468: [XWayland] JavaFX hangs when calling java.awt.Robot.getPixelColor
• 811d08c: 8340010: Fix vectorization tests with compact headers
• 519bb26: 8344217: Remove calls to SecurityManager and doPrivileged in java.net.DatagramSocket and java.net.NetMulticastSocket after JEP 486 integration
• d112f35: 8344855: Remove calls to SecurityManager and doPrivileged in HTTP related implementation classes in the sun.net and sun.net.www.http packages after JEP 486 integration
• da4b7a8: 8341436: containers/docker/TestJcmdWithSideCar.java takes needlessly long to run
• 333a997: 8335231: [macos] Test java/awt/print/PrinterJob/Cancel/PrinterJobCancel.java failed on macOS because the case didn't get the expected PrintAbortException
• 9576546: 8343698: Linux x86_64 lto build gives a lot of warnings and fails lto-wrapper: fatal error: make returned 2 exit status
• 68ba7ee: 8340205: Native linker allows MemoryLayout consisting of only PaddingLayout
• 6f622da: 8344923: Problem list on java/awt/Robot/ScreenCaptureRobotTest.java on macOS
• ... and 30 more: https://git.openjdk.org/jdk/compare/50c099d69e9cef5c38a2624d7c798360eb6c1fba...master

Your commit was automatically rebased without conflicts.

[openjdk]

@asotona Pushed as commit c6b14c6.

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