The JVM is great. It's easy(-ish) to deploy and there is a library for anything you can possibly think of, probably more than one, on Maven. It handles large throughput and big memory usage very well and is extremely tunable.

Using the JVM doesn't mean you're limited to Java anymore, and hasn't for a long time. I have built software for the JVM for the past 6+ years nearly exclusively in Clojure with only a few moments where I needed to dip down into Java proper.