Object declarations

An object can also have a name. This kind of object is called an object declaration:

object Oven {
  fun process(product: Bakeable) {
    println(product.bake())
  }
}

fun main(args: Array<String>) {
    val myAlmondCupcake = Cupcake("Almond")
    Oven.process(myAlmondCupcake)
}

Objects are singletons; you don't need to instantiate Oven to use it. Objects also can extend other types:

interface Oven {
  fun process(product: Bakeable)
}

object ElectricOven: Oven {
  override fun process(product: Bakeable) {
    println(product.bake())
  }
}

fun main(args: Array<String>) {
    val myAlmondCupcake = Cupcake("Almond")
    ElectricOven.process(myAlmondCupcake)
}