Java is good language, I’ve been working with it for more than 20 years. But reality is that big organisation are really slow to adopt new versions and last years I’ve been happy to work at least with Java 8. Comparing to this Kotlin is really a big improvement. Strangely enough it is easier to argue with business to use other language which can be compiled into supported Java version, then get Java version upgrade.
And in general Kotlin have some features, which Java still misses. To name some: null check with
? with possibly to chain and named parameters.