The instructor's explanation of technology according to the flow of the times is really good. Thanks to this, I learned what problems new technologies were born to improve, and it was a lecture that helped me understand the principles themselves as the title suggests without having to remember the theory separately. Although it is not feedback on the lecture, at the end of this lecture, it is recommended to listen to the 'Spring Boot and JPA Practical Complete Conquest Roadmap' after the core principles, but this core principles lecture exists in the MVC curriculum but is excluded from the JPA roadmap. So developers like me who do not use MVC and want to use React, Vue, etc., even if they want to listen to this core principles lecture, they think it was created for the MVC roadmap and are worried about whether they should take it. If you check it out, I think other people will be able to purchase it with peace of mind.