Tomcat 5.x is the current release of Tomcat, and builds upon the Tomcat 3.3 and Tomcat 4.1 codebases. The 5.x releases implement the Servlet 2.4 and JSP 2.0 specifications, which include:
Performance optimizations and reduced garbage collection
Refactored application deployer, with an optional standalone deployer allowing validation and compilation of a web application before putting it in production
Complete server monitoring using JMX and the manager web application
Scalability and reliability enhancements
Improved Taglibs handling, including advanced pooling and tag plugins
Improved platform integration, with native Windows and Unix wrappers
