I second what elusiveshame said about w3schools.com. As far as writing apps for iOS, I believe that the language most often used is Objective C, not Java. I'm not at all involved in anything Apple, so I could be wrong about this.
I believe you're right about iOS development. I don't think java is available on iOS, much like flash isn't supported either. At least I've never seen java being used on iOS, so take that for what it is :p
If you're looking for game dev on iOS, I believe Game Maker exports to iOS (as well as psn), but I haven't done anything in it yet (will be soon, though)