4819544: SwingSet2 JTable Demo throws NullPointerException

[prsadhuk]

In the JTable demo, if we double click on the first cell in the Favorite Number column, delete the value and click on some
other cell, a java.lang.NullPointerException is getting thrown.
The flaw is in the TableDemo's TableModel getColumnClass() method which queries the value of cell 0 in the target column, and returns its Class. This logic seems to be flawed - an NPE will be thrown when the value in cell 0 is null.
Fix by checking for null.

---

Progress

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Issue

• JDK-4819544: SwingSet2 JTable Demo throws NullPointerException

Reviewers

• Pankaj Bansal (@pankaj-bansal - Reviewer) ⚠️ Review applies to 5b181be
• Alexey Ivanov (@aivanov-jdk - Reviewer) ⚠️ Review applies to 5b181be

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[bridgekeeper]

👋 Welcome back psadhukhan! 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]

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• swing

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[mlbridge]

Webrevs

• 01: Full - Incremental (fffb3f32)
• 00: Full (5b181bee)

[pankaj-bansal]

Verified that the NPE is not happening after the fix.

[openjdk]

@prsadhuk 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:

4819544: SwingSet2 JTable Demo throws NullPointerException

Reviewed-by: pbansal, aivanov

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At the time when this comment was updated there had been 134 new commits pushed to the master branch:

• 6c8441f: 8271878: UnProblemList jdk/jfr/event/gc/detailed/TestEvacuationFailedEvent.java in JDK18
• 7728423: 8271895: UnProblemList javax/swing/JComponent/7154030/bug7154030.java in JDK18
• cd6b54e: Merge
• cebcc07: 8271894: ProblemList javax/swing/JComponent/7154030/bug7154030.java in JDK17
• 5f547e8: 8271877: ProblemList jdk/jfr/event/gc/detailed/TestEvacuationFailedEvent.java in JDK17
• 181483b: 8271064: ZGC several jvm08 perf regressions after JDK-8268372
• a007cb1: 8271863: ProblemList serviceability/sa/TestJmapCore.java on linux-x64 with ZGC
• d62fbea: 8271898: disable os.release_multi_mappings_vm on macOS-X64
• 359c708: 8271893: mark hotspot runtime/PerfMemDestroy/PerfMemDestroy.java test as ignoring external VM flags
• a3b0143: 8271887: mark hotspot runtime/CDSCompressedKPtrs tests which ignore external VM flags
• ... and 124 more: https://git.openjdk.java.net/jdk/compare/e4295ccfcdb16041d6f18fd64f7df3f740bf258f...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.

[aivanov-jdk]

Shall the ternary conditional operator be used here?

Suggested change

	if (obj != null) {
	return obj.getClass();
	}
	return Object.class;
	return obj != null ? obj.getClass() : Object.class;

[prsadhuk]

/integrate

[openjdk]

Going to push as commit 64d18d4.
Since your change was applied there have been 134 commits pushed to the master branch:

• 6c8441f: 8271878: UnProblemList jdk/jfr/event/gc/detailed/TestEvacuationFailedEvent.java in JDK18
• 7728423: 8271895: UnProblemList javax/swing/JComponent/7154030/bug7154030.java in JDK18
• cd6b54e: Merge
• cebcc07: 8271894: ProblemList javax/swing/JComponent/7154030/bug7154030.java in JDK17
• 5f547e8: 8271877: ProblemList jdk/jfr/event/gc/detailed/TestEvacuationFailedEvent.java in JDK17
• 181483b: 8271064: ZGC several jvm08 perf regressions after JDK-8268372
• a007cb1: 8271863: ProblemList serviceability/sa/TestJmapCore.java on linux-x64 with ZGC
• d62fbea: 8271898: disable os.release_multi_mappings_vm on macOS-X64
• 359c708: 8271893: mark hotspot runtime/PerfMemDestroy/PerfMemDestroy.java test as ignoring external VM flags
• a3b0143: 8271887: mark hotspot runtime/CDSCompressedKPtrs tests which ignore external VM flags
• ... and 124 more: https://git.openjdk.java.net/jdk/compare/e4295ccfcdb16041d6f18fd64f7df3f740bf258f...master

Your commit was automatically rebased without conflicts.

[openjdk]

@prsadhuk Pushed as commit 64d18d4.

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