Answer 1

Not long if you put your heart to it. JavaTPoint is a good website to start, and Google's android docs are pretty good too.

Just know the basics. From there, you can go in multiple paths, like learning design patterns, making android apps, writing GUI programs, all sorts of stuff.

Have a good understanding of the basics and find opportunities to apply the things you've learned. When learning new things, put them to use, quiz yourself, make a code, or something else to stick it in your brain forever.

Happy learning! 😎