That's quite a feat in and on itself and makes Kotlin code a lot more robust against subtle bugs (hey, who modified this collection!?).
But in Java, List#filter(...) simply does not exist (you can use a static utility class, but come on, that's not the same thing).
In Kotlin's defense, there's const for constants (which is roughly the same as public static final members in Java), and you can declare top-level functions outside any class (which effectively makes them static).
The main issue is that you cannot use inheritance when writing data classes.
The fact alone that it is null-safe by default should be enough to justify the use of Kotlin over Java.
I'm using kotlin on the server side, and it works like a charm alongside our existing Java code.