Use JDK 24 and enable NullAway's JSpecify mode

[marcphilipp]

Overview

• Use JDK 24 toolchain to run Gradle and Java-related tasks
• Avoid ByteBuddy from trying to use Unsafe
• Enable NullAway's JSpecify mode
• Resolve nullability issues surfaced by NullAway's JSpecify mode

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I hereby agree to the terms of the JUnit Contributor License Agreement.

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Definition of Done

• There are no TODOs left in the code
• Method preconditions are checked and documented in the method's Javadoc
• Coding conventions (e.g. for logging) have been followed
• Change is covered by automated tests including corner cases, errors, and exception handling
• Public API has Javadoc and @API annotations
• Change is documented in the User Guide and Release Notes

[vlsi]

It would be great to stop using sourceCompatibility/targetCompatibility properties

[sdeleuze]

Setting the "release" is indeed better, possible via Gradle JavaCompile options.

[marcphilipp]

It would be great to stop using sourceCompatibility/targetCompatibility properties

Setting the "release" is indeed better, possible via Gradle JavaCompile options.

I've only used them for build logic projects, not production code. I'll change it to use --release instead.

[sormuras]

I'll change it to use --release instead.

Didn't the Eclipse project export feature had issues with this? 🤔

[vlsi]

@marcphilipp , @sdeleuze , @sormuras , it was a pleasure to listen to your talks and comments at IDEA Conf. Many thanks for pushing all this forward.

[marcphilipp]

I'll change it to use --release instead.

Didn't the Eclipse project export feature had issues with this? 🤔

@sormuras Are you referring to the separate setting targeting Eclipse that @sbrannen added in ac0b9c1?

[ALUMINIS650]

Anffything basic i can help with?

[ALUMINIS650]

How do we enable the mode?