Didn't find class “com.google.firebase.provider.FirebaseInitProvider”

Question

Before, my program run well. But When I just updated my Android studio to the latest version (2.2 built on 15-sept-16), I am having the following error. When I built it, it says

Answer 1

I got the same error and resolved it using:

1. Clean/Rebuild your Project.
2. Restart Android Studio.
3. Update all SDK tools and Android Studio.
4. Clear Cache and Clear Data on Device.