Android doesn't run JVM.

Not technically, but practically speaking, you compile to JVM code & then it gets translated. This makes targeting the JVM & Android trivial.

Runtime code generation doesn't work on Android. This means all the reverse dependencies of cglib, for example. That is huge part of JVM ecosystem.

It's not trivial, this is why there are no JVM languages that really run well on Android.

What do you mean by that?

I would say compiled Scala runs well on the Dalvik VM.

All languages that do not need to generate (or load) class files at runtime should work well on Android. And that is because Dalvik does not run class files.

So then why don't we see more non-Java Android apps in the wild? We can only go off of open source apps, I've looked at quite a bit of those and have ran across only a couple that don't use Java.