Ironically Javalin is largely written in Kotlin.

Kotlin (from the perspective of this blog post) stands above both Java and Go here because it's type system is even more expressive, it has null safety and it's less verbose than both.

I love Kotlin because it's unapologetically pragmatic, it largely forgoes ideology and instead focuses on getting things done. Go and Java have ideologies and while I am more partial to the Java ideology over the Go one I would prefer to not have to subscribe to either.