Note that while Mill's first target is Scala builds (as an alternative to SBT) there isn't much reason why Mill shouldn't be usable for other JVM/non-JVM langua

Note that while Mill's first target is Scala builds (as an alternative to SBT) there isn't much reason why Mill shouldn't be usable for other JVM/non-JVM languages too. Mill's core is basically a dependency-graph-based caching task-runner, similar to Bazel, which happens to be written in Scala (rather than Skylark). Scala+Java support is just a bunch of helper methods built on top of that. It should be pretty trivial to make it work for Java-only projects (https://github.com/lihaoyi/mill/issues/145 https://github.com/lihaoyi/mill/issues/145) or write the necessary helper methods to make it work for other languages or platforms.