Hi all! Question that has probably been answered before, but I couldn’t find/understand those answer...

# getting-started

[herlevsen]

Hi all! Question that has probably been answered before, but I couldn’t find/understand those answers:
Why do we need to annotate “value classes” with @JvmInline? Ie. why is it not implied that a “value class” should be inlined? And what is a “value class” without @JvmInline?

[Joffrey]

I guess my answer there can shed some light:
https://stackoverflow.com/questions/68908343/how-are-kotlin-value-classes-different-from-inline-classes/68908472#68908472

[Joffrey]

But in short from the KEEP:

The @JvmInline annotation makes it explicit that something special with this class is going on in JVM, and it enables us to support non-annotated value class in the future Valhalla JVM by compiling them using the capabilities of the Project Valhalla.

[herlevsen]

Thank you, I understand now. Wish they would have kept inline classes and have that imply inlining. Those annotations are unsexy. But oh well..

[Joffrey]

The point is that these annotations will go away when there is a "better" implementation (Valhalla) instead of (or on top of) inlining.
It's "ugly" right now so it can be beautiful in the long run 🙂

[herlevsen]

But I guess inlining doesn’t really make a noticeable performance difference, in day to day business logic code, so I’ll probably just skip those annotations, unless i really need it

[Joffrey]

You can't skip the annotations if you use value class at the moment, you have to use them because it's currently the only way `value class`es are supported on JVM (this is to ensure that new implementations without @JvmInline will be backwards-compatible)

[herlevsen]

Oh, I see

[Stephan Schroeder]

but if you don't care much about the inlining, you can always use a data class to create a typesafe wrapper.