Servlet containers

A Servlet container is a specialized web server that supports Servlet execution. It combines the basic functionality of a web server with certain Java/Servlet specific optimizations and extensions – such as an integrated Java runtime environment, and the ability to automatically translate specific URLs into Servlet requests. Individual Servlets are registered with a Servlet container, providing the container with information about what functionality they provide, and what URL or other resource locator they will use to identify themselves. The Servlet container is then able to initialize the Servlet as necessary and deliver requests to the Servlet as they arrive. Many containers have the ability to dynamically add and remove Servlets from the system, allowing new Servlets to quickly be deployed or removed without affecting other Servlets running from the same container. Servlet containers are also referred to as web containers or web engines.

Like the other Java APIs, different vendors provide their own implementation of the Servlet container standard. For a list of some of the free and commercial web containers, see the list of Servlet containers. (Note that 'free' means that non-commercial use is free. Some of the commercial containers, e.g. Resin and Orion, are free to use in a server environment for non-profit organizations).