Excalibur is a platform for component and container applications
built on key design patterns such as Inversion of Control and
Separation of Concerns available for the Java platform. You can
use Excalibur to build any number of other applications from
desktop centric Swing apps to complicated servers. The Avalon
Framework (the core of Excalibur) is often used as the
"underpinning" of a larger application or platform. Such
applications include Apache Cocoon, Apache James, and the Keel
Framework. Excalibur is not part of the J2EE stack. While
Excalibur can be used in developing J2EE applications and even
used to build a J2EE server, the platform is not part of J2EE or
a J2EE application server. Excalibur is much simpler and does not
include many J2EE specifications out of the box. That said, you
might write a J2EE application which embeds Excalibur (such as in
a servlet) or you may embed a J2EE server in a larger
Excalibur-based container. The Excalibur platform is the
following: * A core framework for component programming (The
Avalon Framework)

* An IoC container called Fortress

* A set of container utilities called ContainerKit

* A component library called Cornerstone When working with Excalibur
you may use one or all of these.