The Plumbing
		So what are these value added services that EJBs give us? EJBs provide a place for business logic, the stuff that makes the program work. They manage the data and its interaction with the database. They can talk to other systems. EJBs do not handle presentation.  That's left up to the GUI.  But the beauty is, you can plug any GUI you want into an EJB.  That's the whole idea, since EJBs are based on re-usable logic. EJBs serve as the business logic tier of a 3-tier, or n-tier system. The data are handled by the data tier, or the database. The presentation can be handled by the GUI entirely.  Or it can be split up with a presentation tier on the server side, and a light client, often a browser, on the client side.  Or, with a web service, there may be no visual presentation at all.  The want ads