The list of supported formats can be split up in 2 categories: vector data and raster image data. All are accessed through so-called LayerModels, which are abstractions capable of accessing of the data underneath.
Vector based layer models:
Geotools : support for shape file, WFS (Web Feature Service), PostGIS, DB2, JDBC, ArcSDE, ...
Hibernate Spatial : support for PostGIS, Oracle, MySQL
Raster images models:
WMS : Support for Web Map Service.
Google : Supports the Google Maps (default, satellite and hybrid).
Geomajas 1.3.x has support for the following browsers:
Internet Explorer 6 and higher
Mozilla FireFox 2.0 and 3.0
Google Chrome
Safari v 3.1.2
Geomajas has been built from the ground up, to make use of native browser technology. This means that you do not need any plugin to make it work, just your standard browser!
Also thanks to the FireFox and Safari support, geomajas runs on Windows, Linux and Max os X.