Building Scalable and High-Performance Java™ Web Applications Using J2EE™ Technology

Request-Processing Modes

It's tempting to think of request processing as something only a Web server does. In fact, there are infinite request-processing scenarios—any client can, conceivably, make a request of any other server or subsystem. For all of these scenarios, there are in fact only two modes of request processing: synchronous and asynchronous. We now turn our attention to understanding the pros and cons of both.

Synchronous Communication

Synchronous request processing involves a mode of communication in which the client contacts a server and waits for a reply. Typically, the reply will contain meaningful information in the sense that the value contained in the reply is important to the client. For example, when users click on a Web ...