Kotlin has stuff that's unlikely to appear in Java, such as reified generics - Java has already chosen type erasure generics instead. I wouldn't bet a penny that they ever change this approach if they didn't go with it from the start.
In fact Kotlin doesn't have reified generics. This idea was planned in the beginning and was reflected in the old docs but abandoned later. I believe there's no reference to reified generics on the new web site anymore.
Java is getting reified generics via a really cool mechanism called classdynamic (which also enables efficient implementation of tuples). This is pretty much necessitated by value types. See project Valhalla: http://www.infoq.com/news/2014/07/Project-Valhalla
