Mastering Kotlin

Default methods

Like in Java 8, Kotlin interfaces provide a default implementation for methods. To add a default implementation, we can define a function body within the interface declaration:

interface GameObject {    val id: String        get() = "defaultId"        fun update(currentTime: Long){        println("id: $id update:")    }}

In this example, we've added a default implementation for the GameObject.update method. If an interface provides a default implementation, it does not need to be overridden in an implementing class:

class Player : Movable {    override fun move(currentTime: Long) {        // add logic    }}

You'll see in this example, that Player implements Movable, but does not need to override update:

class Player : Movable {    override fun move(currentTime: