As a junior developer, while applying hexagonal architecture in development with only a very basic level of knowledge, I encountered this lecture. Through the course, I was able to clearly organize concepts that I had not properly understood or had misunderstood. It was a great help that the lecture deeply and meticulously explained points where junior developers often get confused, or content that is usually easy to overlook. When developing, there are many cases where one simply follows trends like "they say this is how it's done nowadays" or "they say that's good," but this lecture went beyond such trends and pointed out why things should be done that way and on what basis they were designed, which was very impressive. What particularly stands out is that it explained the basis of concepts using official documents like RFC standards, and also taught how to efficiently apply them to Spring. Furthermore, when unexpected bugs or exceptional situations arose during the lecture, I learned a lot by observing the process of resolving them. I believe the debugging process, which involves interpreting error messages and analyzing the current situation to infer the cause, is an indispensable and important part of development. Personally, it was a valuable experience, like pair programming with 토비님, and I highly recommend it to other developers to experience at least once. 😊