I tried eclipse-kotlin plugin, and it's nowhere production ready. I'd like to introduce kotlin to colleges, but sadly, it's no good. Kotlin advertise support for Eclipse/NetBeans in the official FAQ, but it's more like a joke, especially that NetBeans plugin had been deprecared and has 0 development since 2016. It seems like JB is more focused on big Android market (they even postpone some features like jlink modularization support by almost a year because of this).