I am a first-year Android developer. I started developing Android by taking Professor Oh Jun-seok's class since I was a student. This lecture is really necessary and it teaches the latest trend technology, so it was really helpful for me while I was working. The intro part that quickly re-understood Kotlin was good, and the convenient functions of Jetpack that can be promoted as the latest trend technology. Personally, using Retrofit and making Rest API processing, MVVM pattern, etc. in an actual app example was really! really! The best part for organizing and understanding the concepts. I had only heard about dependency injection, and it still feels a little difficult, but I thought it was the way to become an intermediate developer. I always respect the professor who works hard to create such high-quality lectures. I have no doubt that this lecture will be very helpful to juniors like me.