Jakarta Tomcat is a web server written in 100% Pure Java. The
Tomcat 4 branch is the reference implementation for the Java
Servlet 2.3 and JavaServer Pages 1.2 technologies.

The Tomcat 4.0.x series are being replaced by the Tomcat 4.1.x
series, which is a refactoring of 4.0 with some minor feature
enhancements.

WWW: http://jakarta.apache.org/tomcat/