It's a perpetual discussion. Java enthusiasts will generally say there is no or only a small difference, while at the same time being excited about Java getting

It's a perpetual discussion. Java enthusiasts will generally say there is no or only a small difference, while at the same time being excited about Java getting features that Kotlin has had years before (e.g. smart casting). In general Java is getting better but more weighed down by legacy and existing design decisions than Kotlin, so a lot of improvements from Kotlin are not possible to be made in Java. Java is running ahead of Kotlin in a few things, mainly virtual threads which don't require black-red functions like coroutines.