I find this java course in Sololearn Interesting but incomplete.

Question

I learn more in challenges rather than courses.
Where can I get interactive course like this?
I have already started with e books. I would like this kind of coding challenges with examples.
Core Oops;
creating library functions;
interactivity in programming;
Encryption and decryption;
Way to store and retrieve sensitive information.

Any website or app or books... pls recommend.
Thanks

Answer 1

Jave recources :
https://www.sololearn.com/discuss/580291/?ref=app