Servlet

A servlet is a Java technology based web component, managed by a container, that generates dynamic content. Like other Java-based components, servlets are platform independent Java classes that are compiled to platform neutral bytecode that can be loaded dynamically into and run by a Java enabled web server. Containers, sometimes called servlet engines, are web server extensions that provide servlet functionality. Servlets interact with web clients via a request/response paradigm implemented by the servlet container.

In functionality, servlets lie somewhere between Common Gateway Interface (CGI) programs and proprietary server extensions such as the Netscape Server API (NSAPI) or Apache Modules. Servlets have the following advantages over other server extension mechanisms:
• They are generally much faster than CGI scripts because a different process model is used.
• They use a standard API that is supported by many web servers.
• They have all the advantages of the Java programming language, including ease of development and platform independence.
• They can access the large set of APIs available for the Java platform.