Take your .war file, drop it onto JBoss. It deploys across the cluster in a zero downtime manner, isolates configuration, provides consistent log structure, cert management, deployment. You can deploy dozens of small war's to the same server and they can talk to each other. Load balance across the cluster automatically based on actual load. Run scheduled jobs and load balance the scheduled jobs themselves. Allow them to be isolated and unique within the cluster.

I may not like Java as a language, but from an infrastructure standpoint Java was basically Heroku long before Heroku was Heroku. The infrastructure is just...solid. The downside was that the XML config stuff was just messy.