Java is the standard for JVM. However, if Java was the perfect tool for any job, no other language would have been implemented over JVM.
I would rather use Kotlin than Java, who, to me, seems bloated and ancient. Also Java, the greater programming environment, kind of forces all things to be objects, unneeded inheritance, unneeded abstraction and patterns on top of patterns. I kind of like to use a more data oriented approach than object oriented approach, or pattern oriented approach, or Uncle Bob oriented approach. I strongly think that the shortest path is the best path, the less abstraction the better, the less CPU cycles used for something, the better.