Add Java 14 CI

[snicoll]

With Java 14 now in release candidate phase, we ned to add a compatibility build to 2.3. There are two things to consider when doing so:

• Gradle does not support Java 14 so we'll have to install two different JDKs (one to run Gradle and one to compile & tests the code). The following section of the Gradle doc is related
• An upgrade to Groovy 3 is required. This is transparent but the CLI (see Upgrade to Groovy 3.0.0 #20119). The plan is to override the version of Groovy and ignore the CLI for the time being.

[dreis2211]

This time you beat me to it :D

[snicoll]

Ah ah. PR still most welcome :-)

[dreis2211]

I can offer to provide some stuff for JDK 14 in general in smaller chunks, if that's okay for you? I already have a couple of things ( see my jdk-14-wip branch ) but to make one big PR at which end we have a (green) CI for JDK 14 I'm missing the time, at the moment. I could offer the following 3 PRs (or at least independent commits) for now based on the WIP branch - given that you generally agree with the way I did things in the branch ;-) :

• Implement possibility to specify custom java home (so you can play around with it too locally)
• Fix JarFileTests for multi release jars on JDK 14
• Fix NoSuchBeanDefinitionFailureAnalyzerTests on JDK 14 (see JDK-8164819 & related tickets for the background )

Let me know what you think.
Cheers,
Christoph

[snicoll]

Thanks @dreis2211. The first sounds like a good start. As for the two others, a single PR should work. The next step is to crate an image that allows CI to run the build with Java 14.

[dreis2211]

It looks like we might get a Groovy 2.5.10 release with JDK 14 compatibility.

[snicoll]

Closing in favour of PR #20413