Jetty is a very popular fast and light servlet container for the JVM. One of the most popular ways to deploy it is embedding it, so you build your app, and include the jetty "engine" inside your app - either via maven, or programmatically wiring it up etc - the main thing is you end up with a jar that is executable, has all it needs to run in place.
Jetty is used in many places, including GAE.
You can run Jetty on cloudbees - this Clickstart sets it up for you - as an embedded app running on a "bare" JVM (along with a build and source repo).
Read on to see how it works - it is pretty easy to do (main thing is to produce an executable jar that looks in the System property "app.port" to get what port to listen on).