If you don't cleanly separate, the day you'll want to write an another client (Android, iOS) you'll loose a lot of valuable time refactoring or worse, duplicati

If you don't cleanly separate, the day you'll want to write an another client (Android, iOS) you'll loose a lot of valuable time refactoring or worse, duplicating code. Separation of concerns is a good reason, too. Spring MVC is also fine, in the end what's important is what we're effective with. I prefers to use standards, thought. An anotehr reason to use a container: you won't mess with the configuration in your code. Normally, you just use JNDI name for resources lookup in you app and let the container admin manage these resources (configuration of the db, db caching, javamail conf, etc etc). A kind of another separation of concerns.