window.addMouseListener(object : MouseAdapter() {

    override fun mouseClicked(e: MouseEvent) {

        // ...

    }

​

    override fun mouseEntered(e: MouseEvent) {

        // ...

    }

})

fun main(args: Array<String>) {

​

    val a = 12

    val b = 13

    val max: Int

​

    max = if (a > b) a else b

    println("$max")

}

open class Person() {

    fun eat() = println("Eating food.")

​

    fun talk() = println("Talking with people.")

​

    open fun pray() = println("Praying god.")

}

​

fun main(args: Array<String>) {

    val atheist = object : Person() {

        override fun pray() = println("I don't pray. I am an atheist.")

    }

​

    atheist.eat()

    atheist.talk()

    atheist.pray()

}