How is `Any` or `Nothing` type mapped at runtime?

# announcements

[ashishkrishnan]

How is Any or Nothing type mapped at runtime?

[Shawn]

what do you mean?

[Shawn]

Any roughly corresponds to Object

[ashishkrishnan]

I mean, how does JVM deal with these types which are unknown to it

[ashishkrishnan]

at compile time as per the docs.

[Shawn]

using the Kotlin Bytecode view, it looks like Nothing turns into Ljava/lang/Void and Any turns into Ljava/lang/Object

[Shawn]

Try it for yourself:

val any: Any = ""
val nothing = null

Tools -> Kotlin -> Show Kotlin Bytecode

[ashishkrishnan]

difference that Any brings to the language?

[Czar]

I'm not aware of any deep details of Any vs Object, but it arguably sounds better than Object as a type.
Nothing on the other hand is a different fruit: https://kotlinlang.org/docs/reference/java-to-kotlin-interop.html#translation-of-type-nothing

[Czar]

I highly recommend to watch this video:

https://youtu.be/Uizh2WlJtnk▾

Or read Kotlin in Action

[Shawn]

@Czar +1 for that link, didn’t realize that was covered in the docs

[Czar]

Problem is some of it still isn't covered (at least I haven't seen it yet, but it is in the book and as far as I remember in the video I've shared)

[Czar]

I mean `Nothing`'s effect on the flow

[ashishkrishnan]

Awesome @Czar. Will take a look. TY.

[Czar]

Sure 🙂

[Czar]

Yup, confirmed, it is covered in the video, if you don't have time to watch it all, the Unit/Void/Nothing is covered starting from 12th minute

[ashishkrishnan]

Will watch it all.

[ashishkrishnan]

Also, need to get the book. "Kotlin in action" right?

[Czar]

yup, written by the authors of the language and has a lot of information useful in practice