Error: No Java files found which extend CordovaActivity
When trying to deploy your App to a connected device with the following command:
ionic run android
Then the solution might seem a little bit radical but, is in fact, quite quick and easy to implement...
From your command line (and assuming you are located in the root of your project) simply issue the following instruction to completely remove the Android platform from your Ionic project:
ionic platform rm android
Then, once that has completed, issue the following command line instruction to install the Android platform:
ionic platform add android
It might seem bizarre but removing and re-installing the Android platform was the quickest and cleanest solution that worked for us.
Now, when you try deploying your App to an Android device, you shouldn't see that error occurring anymore.