I am going to date myself as 'an old guy' here: I used to love building monolithic systems around Apache Tomcat. I would use background threads registered to a

I am going to date myself as 'an old guy' here: I used to love building monolithic systems around Apache Tomcat. I would use background threads registered to a web app to perform background periodic processing and write the web interface using JSP (supports a fast edit/test loop). I would build an uber-JAR file that contained everything including a thin main method to start Tomcat with my app. Totally self contained (except for requiring a JDK or JRE install), easy on memory requirements, and very efficient. A bonus: if an app requires static files, they can be added to a JAR file and opened as resource streams so `everything` really is in one JAR file. Contrast this to J2EE that I would only use reluctantly if a customer wanted to go that way.