Support Java > 15 and Datanucleus 6

[aley2003]

It would be nice if datanucleus-gradle-plugin could support higher Java versions than 15.
If I try to build my project for Datanucleus 6.0.3 and Java 17 I get strange ASM errors.
Perhaps this is related to
//Forcing toolchain use to 15. Newer JDK versions cause ASMEnhancer to fail for some obscure reason languageVersion = JavaLanguageVersion.of(8)
in build.gradle.
Perhaps is solved with ASM 9.4 used by Datanucleus 6.0.3?

[rm3l]

Thanks for reporting this. Interested in opening up a PR for this?

[aley2003]

To be honest, I have a running version of your plugin with Datanucleus 6, Java 17 and gradle 8.1.1 on Windows.
For Windows I had had to change some path handling in tests ('/' vs. '\').
I had fixed some Closure to Closure<?> too.
I think the new version will not work for Datanucleus 5 any longer.
To get my version deployable for all I need to backport it to Java 11.
Should I try it?
Which gradle wrapper version should I use (8.2.1?)?

[thc202]

The plugin is still being built with Java 8, in CI.

[aley2003]

Datanucleus 6 needs Java version 11 at least

[thc202]

What version Datanucleus needs is not a requirement for Gradle/plugin, in any case just saying the minimum version the plugin is currently targeting (I don't mind the bump, already using newer Java versions than 8).

[aley2003]

If I revert the java.toolchain.languageVersion to 8 I get

bad class file: ...\datanucleus-core-6.0.4.jar(org/datanucleus/store/schema/SchemaTool.class)
    class file has wrong version 55.0, should be 52.0

So I think we do need Java 11 to support Datanucleus 6.

[thc202]

That assumes the plugin would not be updated to allow to specify a toolchain for Datanucleus tasks.

[aley2003]

Do you talk about an additional toolchain for Datanucleus tasks?
Can you please explain how this could work and why we would need this?

Every project using Datanucleus 6 will need Java 11 at least.
So every user of datanucleus-gradle-plugin for Datanucleus 6 will have Java 11 at least.

[aley2003]

I have created PR #521