Geomajas Community Documentation
Geomajas is an extensible frameworks which can be extended by including additional plug-ins on the class path when the application is started.
Some of the possible extensions include
adding security services.
providing specific rendering pipeline which modify the default rendering.
additional services which may be used (also by by other plug-ins), for example printing support.
a different face (in principle a face is just another plug-in, the term "face" is used when the plug-in produces data or makes data available to the outside world).
access to a kind of data store (these are referred to as "layer" plug-ins, they consume data).