Kotlin Programming: The Big Nerd Ranch Guide, First Edition

For the More Curious: Initialization Gotchas

You saw earlier in the chapter that order is important when using initializer blocks – you must ensure that all properties used in the block are initialized before the initializer block is defined. Take a look at the following code that shows this initializer block ordering problem:

    class Player() {
        init {
            val healthBonus = health.times(3)
        }

        val health = 100
    }

    fun main(args: Array<String>) {
        Player()
    }

This code would not compile, because the health property is not initialized at the point that it is used by the init block. As we mentioned earlier, when a property is used within an init block, the property initialization must happen before it is accessed. When health is defined before ...