As Java has such a huge existing ecosystem it will be hard for a language like Kotlin to suddenly rise and take over in such a short amount of time. It is everywhere as Sun/Oracle always claim.

Google's Android Studio 3.0 dev environment has just become available in the stable channel, with built-in support for Kotlin and Java 8.

Java may still be the first programming language that springs to mind when you think about Android, but you don’t have to use Java for Android development. In fact, Kotlin is now Google’s ...

Starting with Android Studio 3.0, Kotlin is included out-of-the-box, so there are no additional setup steps or add-ons to install. Kotlin was created by JetBrains and officially released early ...