About Servlets

Servlets, like applets, are reusable Java applications. Servlets, however, run on a web server rather than in a web browser.

Servlets provide a component-based, platform-independent method for building web-based applications without the performance overheads, process limitations, and platform-specific liabilities of CGI programs.

Servlets supported by the Web Server are based on the Java Servlet 2.5 specification. Servlets are created compiled and packed into a Java web application archive WAR file and then deployed to the Web Server and managed at runtime by the servlet engine

Basic characteristics of servlets include the following:

• Operate on input data that is encapsulated in a request object

• Respond to a query with data encapsulated in a response object

• Provide user session information persistence between interactions

• Allow dynamic reloading while the server is running

• Can be addressed with URLs. For examples, buttons on an application's pages often point to servlets

• Can call other servlets and/or JSP pages