I was using a different server language, and I wanted to study Kotlin + Spring Boot, but I thought it would take a long time to find everything on my own, so I listened to this old lecture because the reviews were good and the price was not expensive~! I think it would be okay to find the parts I need in the future by just listening to this lecture. Since it was an old lecture, I had to look for the last part related to swagger again, but since this class also shows a preview, I think it doesn't matter. One thing that's unfortunate is that the JPA lecture hasn't been uploaded even though a lot of time has passed. I'll look for it and write it down.