It was good that the content of the book, which is less than 100 pages, was explained in detail with key points and perfect strategies in about 13 hours. After reading the book once and taking the lecture, I understood the lecture better, and even if I read the book several times on my own, if I don't have basic knowledge, I wouldn't understand it, so it was very helpful to understand it by dividing the explanation of the book and the keywords covered in the book. However, what was disappointing was that there were many lecture PPLs throughout the lecture, so there were times when I lost focus. There were many mentions of the Java series and design pattern lectures, and if there were many lecture references in each video (I understand and am familiar with the fact that these lectures are important as prior knowledge and reference content), I wonder if it would have been better to create a separate video explaining Gi-seon's existing related lectures related to this lecture, just like the Spring Framework Core Technology lecture, where the lecture introduction and instructor introduction were separated, and explain only the learning content in the lecture. I think it would be good for reviewing, learning, and referring to the lecture correlation. Despite the shortcomings, I will definitely watch the next lecture if it is released. I hope you continue to provide good lectures^^