If you digest the contents of this lecture, your skills will definitely improve. However, if you make a diagram of the code used in the lecture and provide it in a diagram format before and after, it would be much easier for the students taking the lecture to understand and understand it. (In this sense, it is not a lecture that is spoon-fed, but a lecture that is a bit uncomfortable.) I am also planning to take the Effective Java lecture, so I am writing a review because I hope it is reflected in the lecture.