Android: How to add "non-native" Java Code?

[FlorianKirmaier]

I would have the need to add some simple "normal"/nongraal classes to an android application.
In my case, I don't even have to communicate between the Davlik and the GraalVM code.
It would be nice to have a simple sample, on how to add "normal"/nongraal JavaCode.
Something similar would be very useful for iOS.

I see some code in attach about this topic https://github.com/gluonhq/attach/blob/master/gradle/native-build.gradle
But it's not quite clear how to do it outside of a library. What would be the best way to achieve this?