I'm halfway through. It's so much fun! It feels like I'm taking an operating system class again during my undergraduate years. At the time, I did the practical training with C language code, so it was a bit boring, but it's much more fun now that I'm doing it with Java, my main language. ㅎㅎ In addition, while studying the lectures, I'm trying to understand the exception cases while experimenting, and the instructor prepares the examples so meticulously, so it's really great. (How do these exception cases work?? => I'll explain it with an example in the next lecture.)