Introspectively, I found that I could achieve a large portion of the Kotlin features with Java8+JavaRX+Lombok but I could see a very strong argument for "Why do

Introspectively, I found that I could achieve a large portion of the Kotlin features with Java8+JavaRX+Lombok but I could see a very strong argument for "Why do I have to learn 3 technologies when I can get everything for free with Kotlin". Additionally, Kotlin is highly recommended from the folks at Google with regards to Android.