Kotlin - why do I get a KotlinNullPointerException

Question

Consider the following code:

Example

fun main(args: Array) {
    maybeWriteMessage()
}

fun maybeWriteMessage(message:         


        

Answer 1

Operator !! throws an KotlinNullPointerException if message is null.

You can read about it here: https://kotlinlang.org/docs/reference/null-safety.html#the--operator