I ended up with a mix when I wanted to run my app on top of a Jetty server. There are projects like jetty-rackup, but when you're on top of the JVM sometimes yo

I ended up with a mix when I wanted to run my app on top of a Jetty server. There are projects like jetty-rackup, but when you're on top of the JVM sometimes you feel the need to throw a servlet for a problematic endpoint in there, or some middleware like a filter that you could use for websockets or some library that doesn't already have wrappers packed up as a gem and so on. JRuby is great, all I'm saying is that when you feel the taste of a competent virtual machine there's no going back :-)