are there any resources anywhere explaining how to release a project with both java and kotlin parts?

tipsy: I don’t think there are any special steps needed, they are interoperable and the release process should be the same

but won't there be kotlin parts that only kotlin-users will be able to use?

The Kotlin code will get compiled to JVM code, so it’s basically the same as Java source code. Yup, the best way is to try it out yourself David 🙂