In Conclusion Page 6
If the software vendors have it right, Web developers will soon need to bust apart their notion of applications into many smaller pieces -- into Web services. If we speak of an "inventory control" application it may actually consist of many components (objects) that exist on several different servers (database servers, processing servers, Web services servers). Management of Web services is not something envisioned for Web servers, or even Web server add-ons -- its a role tailor-made for application servers because they already specialize in controlling and integrating distributed applications. Within the next three years, Web services alone could be the major reason for adding application servers to the server mix.
So far this tutorial makes it sound like an application server may be the answer to lifting the burden from overloaded Web servers -- and an overloaded Web staff. It can, but there should be no illusions about the step into application servers. They are a specialized and complex piece of software, often requiring detailed knowledge of database management, Java, XML, and security procedures -- as well as special knowledge more or less unique to application servers. In short, they usually require people who become specialized in their use. This is expensive and opens the door to management difficulties. Consequently, the move to use application servers should be considered not only in the light of site traffic and application complexity, but also within the context of people available to establish and manage them.