Another interesting MOOC for Java developer

I've just completed the EdX MOOC Data Structures and Software Design by University of Pennsylvania. I would suggest it to someone with a high-beginner or lower-intermediate experience as Java software developer. I think that the lessons would sound reasonably interesting even if your level is higher, however you could be get a bit bored by the exercises - kind of too simple. This is why I didn't push anything on my GitHub account. To have some fun, I didn't use any IDE, just solved the problems in the old way, using a dumb editor, compiling and running them from command line :D Homework 11 is, in my opinion, the most interesting one in the course. We have to refactor a poorly written, albeit working, piece of code to make it fast enough to match the requirements.