Hello, Younghan. After completing the Spring Core Principles Basics course, I also completed the HTTP Web Basics course. This course was actually conceptual, so there were many boring parts, but I think I was able to reduce the boring parts by explaining them with practical examples here and there. I also gained a lot from this course. In the past, as an app developer, I simply requested Restful APIs, displayed them on the UI, and requested or processed data according to the business logic. Since I only knew GET and POST without any knowledge of HTTP, I often had difficulty communicating with web developers. When I had to analyze or modify the source code created by others, I always used addHeader and other parts defined in the webview or cookie manager without knowing what they meant. (Even if I knew, it was only Content-type... It was a serious level.) After reading this course once, I think I got a feel for it. Not only web developers, but also app developers need to have this knowledge, but I think I lived as a developer without much knowledge. I don't know about JPA yet, but I plan to buy and listen to the entire Spring Complete Conquest Roadmap. I look forward to hearing from you in the next MVC lecture!