Geotk requires Java 6. No extension is required for the referencing and metadata modules. However if the coverage module is also used, then Geotk requires also the Java Advanced Imaging library. Note that this library is pre-installed on MacOS X.
While not mandatory, the referencing module works better with a connection to an EPSG database. The database will be created automatically if the geotk-epsg.jar file is available on the classpath, together with one of the following dependencies:
By default, the database is created in a Geotoolkit.org sub-directory in the user application directory. This is always a sub-directory of the user home directory, but the complete path is platform-dependent ("Application Data" on Windows, "Library" on MacOS, the home directory on Linux). The directory can be changed by running the graphical application provided in the geotk-setup module.
The above-cited Setup application can also create the EPSG database on PostgreSQL, using connection parameters which must be explicitly specified.