During that time, I learned Spring education superficially and went into practice, so I didn't even know the core principles and just thought, 'It works like this, so I should do it like this~'. One day, I saw myself struggling to catch a very simple error that I could have solved quickly if I had just known the core principles, so I thought that I shouldn't do this, so I looked for a Spring lecture and came across a lecture by Younghan, who I became a fan of after reading the JPA book. If you've been drawing Spring sketches, you can now draw Spring borders through this lecture. Through the next series of lectures, you can color Spring and draw eyes, noses, and mouths. Thank you for teaching in a really friendly and fun way~!