I still don't see how Kotlin is involved. People drafting JEPs are well aware of how modern languages, including the ones running on the JVM, have evolved in the past decades. Kotlin is pretty late to the party and hasn't really brought anything new to the JVM (by choice), except for coroutines maybe.

Edit: see pron's comment below.

Here's a quote from Reynolds, one of the creators of Spark:

> The primary issue I can think of comes from the lack of pattern matching. Kotlin’s language designer left out pattern matching intentionally because it is a complex feature whose use case is primarily for building compilers. However, modern Spark (post Catalyst / Tungsten) look a lot like compilers and as a result the internals would become more verbose if built using a language that doesn't support pattern matching.

Source: https://www.quora.com/profile/Reynold-Xin

You can find some discussion and good examples here: https://discuss.kotlinlang.org/t/destructuring-in-when/2391/...