I've read some of your posts over the last years and you're much more of a jack of all trades than me - I couldn't put together a hello world html site without looking it up.
As for how I'm learning Java, I took one beginner course at udacity:
https://www.udacity.com/course/intro...ramming--cs046
which I really liked, having tried a bunch of similar courses on Java and C# before but they were all too easy or not interactive enough. I destroyed their final exam (a connect 4 bot) and hung around in their community for a couple of weeks, helping other "students", which helped me a lot, too.
After that I started their android developer course, which has a 1 year Java requirement, after talking with some coaches I decided to give it a try but realized pretty soon I was in over my head - I would have still been able to complete it, but it was a slow battle, having to stop and learn a completely new concept for a day, every other 10 minute lesson.
Skill-wise, I felt I was in a spot where beginner tutorials and books wouldn't teach me anything new but I wasn't good enough for intermediate stuff so from then on I build my own small projects (rhyme generator, tiny game prototypes) which I obv never finished but I learned a lot along the way.
The game I'm working on right now I'm sure you could do yourself, it uses:
libgdx for the android (and pc) client, graphics, sound, input
kryonet for networking
MongoDB to, well, save and stuff
Server and client are written in simple Java and being a turn-based game helps a lot (It's like a roguelike party-based jrpg).
Like I said, I'm still pretty bad at everything I do, but I feel it wouldn't take long for me to get competent in a specific domain if I had the guidance, structure etc, which a bootcamp or trainee-ship can hopefully provide - but I'm less sure about my prospects of getting hired, due to my age and lack of experience.