I took a Java language class when I was an undergraduate, but I don't remember much and I don't feel like I understood it properly, but rather just learned the basic grammar. At first, it felt a little boring because it covered too much easy content for majors, but there were useful shortcuts and basic skills that I learned by memorizing between the easy content, so I felt it was very beneficial. In particular, I have seen many cases where polymorphism and OCP are explained only conceptually and passed over, but it was much easier to understand when I listened to the explanation through example problems. Thanks to that, I feel confident that I have definitely mastered the basics. Thank you so much for the great lecture. Now I have to go listen to the intermediate level😊😊