Geronimo - the chief!

Geronimo, the Apache Software Foundation's J2EE 1.4 server project, is integrating a large suite of existing open source services to achieve J2EE 1.4 compliance. Part 1 of this two-part series explors the reason for Geronimo, its design goals and architecture, and some core concepts and terminology. In the second part, Sing Li cuts to the chase and gets hands-on with Geronimo. Using the latest Geronimo distribution, you'll test and deploy a Web application, an enterprise application, Enterprise Java™Beans (EJBs), and more.

rating comment: These two articles give you a good overview of Apache's J2EE Server, not only from a user's point of view, but also from a developer's perspective. Covering almost every aspect, these articles give you enough background information to start using and understanding Geronimo.