At 14, it would be truly strange if you knew for sure just what you'll do as an adult. I suggest you do and experience as much as you can. Sports, music, technology, art, etc. Narrowing your interests to just one activity can be called "focused"...but the more usual term is "obsessed".
So, if you're having fun with Java, by all means keep at it. Just don't make it the only thing you do.
Sports are especially good. Physical fitness helps with mental endurance and clarity and will improve every other aspect of your life. Provided that you have other aspects, that is, so don't make sports or any thing else the only thing you do.
More time for school? That depends on how much time you're spending already, I suppose. Certainly, don't neglect your studies. But, it sounds like you've learned a lot of Java on your own, so you know that not all education is formal. Do try to learn from school to, well enough to actually use the information later. Especially in math. Math is the most cumulative subject that's taught. After the World Geography test on Africa, you might never need to know the capital of Ghana the rest of your life. But everything you learn in math will be used again in future classes.
That's a lot of advice. Hope some of it is useful.