Swift on iOS and Kotlin on Android are a great update from their predecessors both in terms of syntax and safety, (Optionals etc.), which I really appreciate. I

Swift on iOS and Kotlin on Android are a great update from their predecessors both in terms of syntax and safety, (Optionals etc.), which I really appreciate. I also like how they both provide just enough functional tools to be interesting and useful, yet at the same time remain firmly in the familiar OO land, makes the adoption cost a lot lower.