Java agent support

[Doikor]

Proper support for java agents would be really nice.

For example SBT has https://github.com/sbt/sbt-javaagent that makes adding an agent into your build easy including configuration for choosing where to use it (run, test, build/docker image, etc)

[lihaoyi]

I don't have recent experience with Java agents (say, in the last 10 years), but this does seem useful. If you are interested in contributing some built in support I'd love to include it