I am looking for an Android Studio Client/Server USB Sample/Example code. I have gotten a basic Java Based Android Studio App built successfully running through Android Studio and debugged by representing it on a physical Samsung Android device through a USB port. What I would like to do now is the following:

1. Build a small Java example code to run separately on Ubuntu that is not necessarily build on Android Studio but some other development platform that can communicate through USB to software build on the first program mentioned here.
2. Build an APK based on the code from the first project mentioned here and deploy it to an Android device.
3. Test the communication between these two programs.