You are asking a lot of questions in that paragraph.
People here will be able to help you with the Arduino stuff but probably not with the Android stuff.
Your reference to Java is a bit confusing. The Arduino system uses C++ as the programming language.
The Android system is written in Java but you can also use other languages. If you don't know anything about Android programming it might be wisest to study that first. By comparison, the Arduino is simple. You might find this link useful.
...R