There are several nice features but the only ones I am likely to use are:
- Local variable type inference
- Better Docker container awareness in Linux
- Improved repl support
I have mixed feelings about the rapid new 6 month release cycles, but I understand the desire to compete with other JVM languages like Kotlin, Scala, Clojure, etc.
I have updating both of my Java books (Power Java and Practical Artificial Intelligence Programming With Java) on my schedule for the next 18 months. Java 11 is slated for release September 2018 and I will probably use Java 11 (whatever it will be!) for the updated books sine Java 11 will be a long term support release.