What is the purpose of empty class in Kotlin?

Question

I was going through Kotlin reference document and then I saw this.

The class declaration consists of the class name, the class header (

Answer 1

Empty classes can be useful to represent state along with other classes, especially when part of a sealed class. Eg.

sealed class MyState {
    class Empty : MyState()
    class Loading : MyState()
    data class Content(content: String) : MyState()
    data class Error(error: Throwable) : MyState()
}

In this way you can think of them like java enum entries with more flexibility.