Wow... Really the entire SpringBoot JPA structure and Kotlin syntax utilization... Amazing! I studied Kotlin syntax by Googling to see if the controllers, services, etc. that I made based on Kotlin in a short period of time were correct, but it took too long, so I took this lecture... I finally got the feel of itㅎㅎ Thank you for the really good lecture up to Querydsl! If you upload the advanced course, I'll go check it out!