I need a refresh.
Depends on what topic/API and also how you prefer to learn really. I learn best by visually watching and then experimenting, changing and breaking code. You might learn better from reading for example. If you give an idea of what you want to learn you can get a nudge in the right direction from there :point:
Also, welcome to the forum!
There’s a bunch of “Which lib do I choose?” threads as well if you want to check them out. What you’re doing right now, however, is useless because you’re giving us no context as to where you are experience-wise. Details, maybe?
Need a refresh of the basics? Go to http://staticvoidgames.com/ They have a bunch of tutorials on Java and Processing.
what do you mean by basics?
java basics?
programming basics?
game programming basics?
opengl basics?
networking and databse basics? 
(just kidding ^^)
maybe explain what you want to have, my chrome bookmarks
are full of stuff like this ^^
^^^ THIS! 
Tutorials Point is awesome and the topics are organized very well, which makes it easy to refresh on the parts you need.