Hello Mr. Bye, first of all, thank you for telling me about various development methods that I was ignorant of. I didn't know much about using various refactoring techniques using IntelliJ. It seems that it is necessary to read the manuals of Springboot and IntelliJ Tool carefully. Also, it was good to use shortcuts through refactoring methods or techniques, but more than anything, it seems good to look at the code level even though I only vaguely understood what TDD is in theory. I learned refactoring methods and shortcuts, but it would be better if there was a way to actually implement test code. I really feel like it comes from the practical experience needed for development. I am a real developer rather than a beginner. Mr. Bye, have a good day in the future and I look forward to the next content :)