Java plugin should not copy all jar files

[vpa1977]

What needs to get done

Java plugin copies all jar files found in the build output. This includes test dependencies which should not be present in the resulting image.
Java plugin is unable to distinguish between test and runtime dependencies as it is build-system specific.
We need to design a way to determine the test dependencies,.

Why it needs to get done

By default Java plugin deploys all the jar files including test dependencies.

[lengau]

I'm not sure how we'd do this computationally in a backwards-compatible manner. A workaround right now is to use stage keywords to remove those.

As you mentioned using the dist subcommand for ant/maven, we might be able to do that as an opt-in option that we can change the default for in 26.04 (or possibly even make the only way in 26.04).

[lengau]

cc @cmatsuoka @tigarmo

[tigarmo]

Right, this would need to be addressed per-specific plugin (maven, ant, etc). I also agree with doing an opt-in for the current plugins, and a breaking change for 26.04

[vpa1977]

Right, this would need to be addressed per-specific plugin (maven, ant, etc). I also agree with doing an opt-in for the current plugins, and a breaking change for 26.04

The solution is more or less clear-cut for ant (we can run dist), but with maven and gradle the line is a bit murkier - the gradle tasks/maven plugins might provide several outputs which are even conflicting with each other (e.g. plain jar with dependencies vs boot jar).

The only way to resolve this is to hook into the build system itself (https://github.com/rockcrafters/java-rockcraft-plugins).

[vpa1977]

Lets add more documentation to maven/ant and explain how to use stage keyword/dist command.