@enough-analyst-54434 So after doing some more digging and thinking about this right now I think that's fine. Groovy, Kotlin and Clojure aren't designed to be built mutually with Java, unlike Scala. The existing ecosystems outside of pants are all designed for phased compilation where you build your Java (typically first) and then your $OTHERLANG which will link against the Java. It looks like it should be reasonable to add at least Clojure and Kotlin as compiler steps which just happen after zinc using the classpath generated by the zinc compile.