Application Servers

The many new products touting themselves as application servers define the fastest-growing segment of the middleware marketplace. What's interesting about this is that application servers are nothing new (and TP monitors should be considered application servers due to their many common features). Most application servers are employed as Web-enabled middleware, processing transactions from Web-enabled applications. What's more, they employ modern languages such as Java, instead of traditional procedural languages such as C and COBOL (common with TP monitors).

Simply put, application servers provide for application logic sharing and processing, and for connections to back-end resources (see Figure 6.13). These resources include databases, ERP applications, and even traditional mainframe applications. Application servers also provide user interface development mechanisms. In addition, they usually provide mechanisms to deploy the application to the Web platform.

Figure 6.13. The architecture of a typical application server.

Application server vendors are repositioning their products as a technology that solves application integration problems (some without the benefit of a technology that works!). This being the case, application servers, as well as TP monitors, are sure to play a major role in the application integration domain. Many of these vendors are going so far as to incorporate features such as messaging, transformation, and intelligent routing, services that are currently native to integration servers. This area of middleware is in the throes of something more than an evolution. It is in the throes of a genuine revolution.