Geographic library
Viking is a free/open source program to manage GPS data
Toolkit for working with and mapping geospatial data
GWC is a tile server and caching proxy written in Java
An information system for cyclists in Berlin and Brandenburg
GPS track editor for editing tracks and planning (multiple) day tours
utilities for cadastre system
Automated detection of the unknown early map projection
Spatial Statistics Libraries & Tools for GeoTools, GeoServer, uDig
Open source system for GPS tracking devices
Set of Java interfaces for geospatial applications
Reading OpenStreetMap Pbf files.
Tool to work on map data, to check the data and generate your own maps
Offline vector map display ported from OsmAnd
Plugins for OpenCPN
Interactive visualization of plate tectonics.