Great job with your app! I'm enjoying playing with it.
Java was a wise language choice given it is the language used by AP Computer Science A courses. I hope you will consider Javascript next, the Github code rankings show it as the most popular language: http://www.wired.com/2015/08/github-data-shows-changing-soft...
Thanks so much for your feedback on Javvy! Yes, Javascript: it's going to happen! By the way, in this article I cite Java as the most popular programming language (based on the TIOBE index): https://medium.com/@hellocode/getting-javvy-or-how-we-re-bri...