Android Studio: Unexpected top level exception (finished with non-zero exit value 2..)

Question

When i\'m trying to debug my android app i\'m getting the following error message:

Error:Execution failed for task \':app:transformClassesWithDexFor

Answer 1

At my case change buildToolsVersion from "24" to "23.0.2", solve the problem especially if you're using old Android Studio less than version 2