Android Studio debugger throws NullPointerException

Question

This problem started yesterday, I try and press the "Debug" button for an app and In the event log I see:

11:24:34 AM NullPointerException: null

and my app wouldn't start. I'm trying to debug on the Emulator, I tried restarting both AS and computer with no help.

If I run the app normally it works fine. Needless to say that 2 days ago same code debugged fine

Anyone has a clue what this might be?

Edit:

That is the only error that appears in the log.

11:30:49 AM Platform and Plugin Updates: A new version of Android Studio is available! (show balloon)
11:31:11 AM Gradle sync started
11:32:07 AM Gradle sync completed
11:32:07 AM Executing tasks: [:app:generateDebugSources, :app:generateDebugAndroidTestSources]
11:32:26 AM Gradle build finished in 18s 592ms
11:34:12 AM Executing tasks: [:app:assembleDebug]
11:34:22 AM Gradle build finished in 10s 315ms
11:34:51 AM NullPointerException: null

Answer 1

Updating Android Studio 1.5 into 2.0 solved the problem. Perhaps even if I re-installed 1.5 it would have fixed it.

Answer 2

停止调试器并清理项目可能会有所帮助