In Kotlin you can do: when (value) { 1 -> ..., 2 -> ..., null -> ... } The compilers doesn't let you forget to check for n

In Kotlin you can do: when (value) { 1 -> ..., 2 -> ..., null -> ... } The compilers doesn't let you forget to check for null. It's smart enough to correctly evaluate and cast nested expression. when (value) { is null -> "nothing to see" is Number -> "a Number: ${value + 1}" is String -> when { it.isBlank() -> "Blank String" null -> /* compiler error, you already checked for null */ else -> it.trim() } } Or val x = value ?: 5 /* use 5 if value is null) val x = value?.some?.nullable?.chain ?: 5 /* use 5 if the chain can't be called */ Or val x = value?.let { /* work on non-null value */ } ?: alternative