Java Servlets

Java Servlets are server-side [[Java]] programs that process and handle client requests and generate dynamic web content. They are a fundamental technology for Java-based web application development, providing a robust and scalable way to extend the capabilities of web servers.

Servlets run on a web server or an application server, handling client requests received over [[HTTP Protocol|HTTP]] and generating responses sent back to the client. Unlike client-side Java applets, servlets do not run in a web browser.

Servlets are used to create dynamic web content, such as [[HTML]], [[Extensible Markup Language|XML]], or [[JavaScript Object Notation|JSON]], in response to client requests. They can also forward requests to other server-side resources (like [[JavaServer Pages (JSP)|JSPs]] or other servlets) for processing.

A servlet goes through specific lifecycle phases managed by the servlet container: initialization (init method), handling client requests (service method), and termination (destroy method).

Servlets are managed by a component called a servlet container, which is part of a web server or an application server like [[Apache Tomcat]]. The container handles the lifecycle of servlets, network communication, and interaction with other web resources.

Servlets offer a fast, efficient, and platform-independent way to build web applications. They can maintain state across multiple requests (session management), interact with databases, and integrate with other Java technologies.

The Java Servlet API provides interfaces and classes for writing servlets. The HttpServlet class is commonly extended to create HTTP-specific servlets. Servlets are often used in conjunction with JavaServer Pages (JSP). While JSPs simplify writing HTML and other output, servlets handle more complex processing tasks.

Servlets are deployed as part of a web application, usually packaged in a [[WAR (Web Application Archive)]] file, and deployed to a servlet container.