Why is 'this::javaclass' used in this context?

See more:

reflection

Kotlin

sealed class Genre{
sealed class Fiction : Genre(){
    object Classics: Fiction()
    object Fantasy: Fiction()
    object ScienceFiction: Fiction()
}
sealed class NonFiction: Genre(){
    object Biography: NonFiction()
    object Business: NonFiction()
    object Feminism: NonFiction()
    object Politics: NonFiction()
    object SelfHelp: NonFiction()
}

override fun toString(): String {
    return this::javaClass.get().simpleName
}

What I have tried:

I can not understand the use of javaClass in kotlin.
And the use of this::javaClass.get().simpleName, is that because we want to access simpleName?
Can you please explain it in simple words and giving examples.
Thanks.