1. Application Servers What is it? General A set of software frameworks, components, utilities, functionality that enables you to develop and deliver n-tiered web applications Specific A software package that implements all of the J2EE APIs and frameworks that allow you to develop and deliver J2EE applications

2. Application Servers A J2EE Application Server provides (at a minimum): Servlet engine/container EJB engine/container Web Server (or ability to integrate with a web server) Concrete implementations of all the J2EE APIs Java Mail Messaging RMI Others… A vendor-bought App Server will also have additional functionality in addition to the J2EE functionality

3. Application Servers Products Full J2EE App Servers BEA Web Logic IBM Websphere Oracle App Server JBoss (FREE / open source) Many others… Others Tomcat (servlet only - FREE) http://www.theserverside.com/reviews/matrix.jsp

4. Application Servers Do I need one? If you want to deliver any kind of web application with java, you at least need a Servlet engine Start with Tomcat, it’s free Many organizations don’t go further than this If high volume / high availability are issues, consider