When studying from books, I didn't really understand MVC's RequestMappingHandlerAdapter and RequestMappingHandlerMapping, but when I made them myself, I was able to experience the structure in my head beyond understanding. Furthermore, I felt that I had improved myself by finding the relevant class and looking at the code directly in the parts I was interested in, and at the same time, I was grateful for making such a lecture. I will continue to study MVC2 and Boot before studying AOP (will you also cover PSA??) in the next new advanced lecture!!