Java™ Network Programming and Distributed Computing

10.2. How Servlets Work

When a client sends a request to a servlet-enabled server that invokes a servlet, the server first checks to see if the servlet is loaded. If it is not, the servlet class is loaded and a new instance is created. The servlet is then initialized by a call to its init() method, which can contain startup code similar to the init() method of an applet. Once the servlet is ready, a call to its service() method is made. This lifecycle is relatively simple, as shown in Figure 10-1. Figure 10-2 shows the process by which a servlet is loaded, initialized, and made ready to service client requests in a servlet-enabled Web server.

Figure 10-1. Servlet life cycle

Figure 10-2. Servlet instantiation, initialization, and processing of ...