There's nothing special about Kotlin. It's a bunch of libraries for runtime and compile time... like anything else you use.
There is a difference between supporting a language with a Notepad++ like experience, and what JetBrains was doing before ramping down the Eclipse plugin team, as means to sell more InteliJ licenses instead.
It compiles fine with Maven or Gradle, it provides auto-prompt/complete/hints. It just works.
And above all, no crashes left and right.
Kotlin is plugins for Maven/Gradle, and classpath libraries. There is no magic going on here...
There's nothing special about Kotlin. It's a bunch of libraries for runtime and compile time... like anything else you use.