A free program for Android, by HiTech Rush Inc.
CodeGym: learn Java is a mobile educational quest game for beginners to professionals. It’s a complete course for beginners to advanced Java programmers. The app is developed to help you learn Java programming in a fast and efficient way. It’s all in one place — 1200 tasks and 600 lectures. It’s an Android-based application that’s compatible with Android devices.
You can choose the time to study, so you don’t have to worry about your busy schedule. All you need to do is install the app, choose the time to study, choose a quest, and start solving. It’s an educational quest, which means you’ll learn a lot.
It’s a mobile application, so you can do your studying wherever you want. You don’t need to be stuck in a classroom or at your desk.