A servlet is a Java programming language class used to extend the capabilities of servers that host applications access via a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by Web servers. Thus, it can be thought of as a Java Applet that runs on a server instead of a browser. A Servlet is a Java-based server-side web technology. As the name implies, it serves a client request and receives a response from the server. Technically speaking, a Servlet is a Java class in Java EE that conforms to the Java Servlet API, a protocol by which a Java class may respond to requests. They are not tied to a specific client-server protocol, but are most often used with the HTTP protocol. Therefore, the word "Servlet" is often used in the meaning of "HTTP Servlet". Thus, a software developer may use a servlet to add dynamic content to a Web server using the Java platform.
Contributions by Elving, Doug Bell, and Spasemunki.