The same reason why my default stack is still Java/Kotlin with Spring and Hibernate. A stable environment, stable runtime that is guaranteed to not change too much and has a culture of backwards compatibility.
How are you liking Java with all the versions that are dropping. Are you still on 8? Correto? Or are you keeping up? and do you see the value in the features that are dropping.
Java is moving a lot faster now with the new 6 month release cadence but you don't need to follow every release. Sticking to LTS releases is fine for projects that require longevity.
Some projects are still using 8 and will be until their EOL date. New projects start on the latest LTS release (11).
java.time is really nice, so I use Java 11 (2018) on my servers. If not using java.time, Java 8 (2014) or later is fine. But I use Clojure, not raw Java. I haven't had any issues with upgrading. If a server works with 8, it works fine with 11 (in my experience).
