People around me say that data structures are very important in practice. Through this lecture, I was able to see examples and codes on what data structures are, how they have developed, what methods are being adopted now, and how they are being utilized. I also liked that Younghan personally organized how to use them in practice. I was able to learn how developers these days use them and how Younghan himself has used them, so many of my questions were resolved! This is my first time studying development and Java, so there are still some difficult parts, but I am having a lot of fun studying because I can organize what I just learned by following the lecture, writing code, and solving problems on my own. I have yet to learn Spring, but since Spring and the language are so vast, I wanted to look back on one cycle following the Spring roadmap even if I don't understand it right away. I also believe that Younghan will do a good job of resolving questions about how development is done, what Spring is, and how it fits in with the Java language. After completing the roadmap once, I want to go back to the beginning and review the basics one more time. Then, I will be able to see things in a broader way! Thank you for always giving great lectures. Please continue to do your best in the future!