eb application servers, the newest class of middleware, are designed to reduce the complexity of developing multitier applications and Web solutions, and to provide scalability for client-server applications. Rather than coding to transaction-processing monitors, application servers provide connection and transaction services that are transparent to the application, says Dave Kelly, VP of application services with the Hurwitz Group IT consulting firm.
Specifically, Web application servers provide a middle-tier infrastructure for managing server code and providing integration services. Typical services include transaction management, load balancing, failover, and security. Application servers also provide connectivity to other middle-tier services and back-end applications and databases. Some products can also perform data conversion and file-format translation between applications.
The selection of an application server should center on the specific connectivity options your applications need.
Bluestone Software's Sapphire, Haht Software's HahtSite, NetDynamics, and Netscape's Kiva have dominated this emerging market, though IBM, Microsoft, Oracle, and Sybase have set their sights on this area as well.