What is Catalina?

Catalina is the reference implementation of the Servlet API specification. It is packaged in Tomcat along with Jasper (the reference implementation of the JavaServer Pages (JSP) specification.

Catalina will also run servlets that conform to the Servlet API specification separately from Jasper. It has no internal code dependencies on Jasper, although Tomcat as a whole includes some code that optimizes performance when Catalina and Jasper are in fact deployed together.

Status

The Catalina code base has a fairly long lifetime (stretching back to when it was going to be the next version of Apache JServ). Current efforts are primarily focused on integrating the new features requried by version 2.3 of the spec (which just entered public draft status), adding the last remaining bits of functionality present in Tomcat 3.x but not yet in Catalina (support for web server connectors and the ability to run a web application under a security policy), and improving performance. The following documents provide a more detailed look at what's going on.

• Implementation of New Servlet 2.3 Features - Summary of the key new features of the Servlet 2.3 draft specification, and describes progress towards implementing them in Catalina.
• Catalina TODO List - List of the high level tasks that need to be completed for Catalina, and includes the names and email addresses of folks who have volunteered to work on the various pieces.

Documentation

The following documents describe the internal architecture of Catalina in more detail.

• Original Proposal for Catalina - The original document that proposed the Catalina architecture, including design goals and an overview of the primary components.
• Architecture of Catalina - High level overview of the current major components of Catalina, and how they interact with each other.
• Building Catalina - Summary of the software prerequisites and steps required to build Catalina (as well as integrate it with Jasper and the example webapps if you want to) using the Tomcat 4.0 source distribution (or a CVS checkout of this code).