Hello! I studied Java through other books and lectures, but no matter how much I read, I couldn't understand anything after constructors, so I gave up on inheritance and polymorphism and looked for other lectures. After watching this lecture, I finally grasped the concept of Java. Of course, I had to review, but I felt like my difficulties were solved while watching the lecture. The lecture first showed me how to write code, and then explained it again easily through the lecture materials, which was very helpful. I finally understood polymorphism, which I didn't understand so much. While listening to the lecture, I thought a lot about it. Thank you for making such a great lecture! I'll be waiting for the intermediate and advanced versions.