It has been a while, but I used to read AOSP source code quite regularly, and always wondered where do all those engineers that pass the famous Google interviews land, because they certainly weren't writing the Java and C++ code in Android, given how it looked like, or the whole mess with NDK headers, and other stuff in the tooling.

Ah, and the Eclipse/Android Studio stable releases, that usually have bugs as if they were still preview, release candidate ones.