I love java and kotlin. The gap has certainly swayed way more in Java's favor over the last 5 years, but there are still a ton of great features that kotlin does first and if that gives java a target to run toward in a lagging way more legacy compatible rock solid way, isn't this just a win for both camps? Just consider kotlin (JVM) to be java-beta with slightly different flourishes, and you wouldn't be too far from the truth. Kotlin is also very big in pushing their other initiatives that aren't entirely directed at JVM at least for now, like cross compilation native targets, compile time serialization primitives, totally structured concurrency, etc