[SPARK-36362] Omnibus Java code static analyzer warning fixes

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.2.0
• Fix Version/s: 3.3.0
• Component/s: Spark Core, SQL, Tests
• Target Version/s: 3.3.0
• Assignee: Sean R. Owen
• Reporter: Sean R. Owen
• Created: 30/Jul/21 17:20
• Updated: 01/Aug/21 07:53
• Resolved: 01/Aug/21 05:36

Description

Inspired by a recent Java code touch-up, I wanted to fix in one pass several lingering non-trivial issues with the Java code that a static analyzer turns up. Only a few of these have material effects, but some do, and figured we could avoid taking N PRs over time to address these.

• Some int*int multiplications that widen to long maybe could overflow
• Unnecessarily non-static inner classes
• Some tests "catch (AssertionError)" and do nothing
• Manual array iteration vs very slightly faster/simpler foreach
• Incorrect generic types that just happen to not cause a runtime error
• Missed opportunities for try-close
• Mutable enums which shouldn't be
• .. and a few other minor things

Issue Links

• links to: [Github] Pull Request #33594 (srowen)
• links to: [Github] Pull Request #33601 (dongjoon-hyun)
• links to: [Github] Pull Request #33601 (dongjoon-hyun)