It looks like there is some issue with update procedure of Android Studio. Especially from version 0.3+ up to the currently newest one (0.4.6). If you keep having “Cannot inherit from final class” the solution for you is simple. Please follow steps below:
1. Close Android Studio application,
2. Open Android Studio folder (the folder where Android Studio is installed into)
3. Enter plugins\gradle\lib folder
4. Remove guava-11.0.*.jar file that you will find there (do not remove guava-sdk5*.jar file!)
Now you can run Android Studio again and the problem should disappear.