A free app for Android, by Thiyagaraaj M.

This free application for the Java programming language will teach you the basics of the language, as well as provide you with an in-depth look at the different types of variables, classes, objects, arrays, and so on. It also comes with a comprehensive collection of sample Java codes, along with a number of exercises to help you test your knowledge.

This is an extremely useful tool for all those interested in learning Java programming, regardless of whether they are a beginner or an expert. It covers a large number of topics and concepts, making it perfect for anyone who wants to learn the language.