All datasources (e.g. PostGIS, Shapefile(tm), GML...) must provide implementations of the DataSource interface and the DataSourceFactorySpi interface. These interfaces allow new types of datasource to be plugged into applications which use geotools without the need to modify any code.

For more information on how to write a new datasource, see the DataSource javadocs, for more infomration on the Service Provider Interface mechanism used to allow dynamic plugins see DataSourceFinder and DataSourceFactorySpi