In fairness, you can just put ? on the end of every type and they will all be nullable like in Java. It can all be mutable state just by writing var instead of

In fairness, you can just put ? on the end of every type and they will all be nullable like in Java. It can all be mutable state just by writing var instead of val. No big deal. The compiler will yell at you if you use a nullable pointer in a place that needs non-null but you can cast it away using !! But I write Kotlin all the time and nullness checking is one of its best features. I wouldn't want to go back.