[izacus]

Well, you can hardly add those features onto devices that don't have them in their standard library. Even now all the features that require modification of the runtime are restricted to the VMs actually supporting them (e.g. try-with-resources since Android 4.4, most other new Java 8 features since Android 6.0 I think).

(Yes, it would be nice if new Android versions would expand the standard library).

In the end I don't see that as a huge restriction - instead of java.time there's ThreetenABP, instead of streams there's better RxJava, etc. With added bonus that you're not limited to whatever libraries device ships with, but you bring your own always up to date ones.

Also, right now, any new project should pretty much be started in Kotlin which does everything that Java 8 does better and is bytecode compatible with Android VMs.