Why does ContentProvider.onCreate() get called before Application.onCreate()?

According a Google's issue it's how this should work (although documentation is wrong).

There's another question that have a workarround that can help you.

It is exactly how it should work.

Documentation of Application class was updated starting from Android 4.2 and it says that Application#onCreate()

Called when the application is starting, before any activity, service, or receiver objects (excluding content providers) have been created.