I'm a developer currently working as a front-end developer! I wanted to study the back-end part, so I asked my colleague, and he said that the back-end lecture is definitely Kim Young-han's lecture. I listened to it and I understand why he recommended it! There aren't many lectures that explain in such detail in an introductory lecture, but I think it was very helpful for the front-end language part because it explained it in such detail! I learned about Java introduction through the Java lecture, but I can also acquire basic knowledge about other languages in addition to Java. ㅎㅎ