It's obvious that you've prepared the lectures really hard, and it was great to be able to learn up to the bottom of Batch. If there's anything to be sorry about, it's that it's too far from clean code..! (For example, when running a for loop based on a List, you first check for size > 0 and then run the for loop.. You could just use stream.anyMatch(), but you waste performance and readability by using filter(), and there are some regrettable parts, such as the package structure, the responsibility and role logic of each domain, etc.) > Please just refer to it. I enjoyed the lecture! 👍