GeoWE is an open free GIS platform oriented to advanced geodata editing on The Web. The main aim of this initiative is to move the strenghts usually linked to desktop GIS to a web environment, by leveraging open source technologies. This is a free software project that is part of the open source GIS world, and it is developed in Java using the Google Web Toolkit framework.
Lets you monitor your GPS-phone. You have full control of your own data. Both client software (for phones) and server software is free open source, so you might set up your own server or use the default one at opengeotracker.org
KartoMNT is a free software of height model digitalization.
This software allows you to create your own Digital Height Models (DHM) with a simple map. Then you'll be able to visualize DHMs with the KartoMNT 3D viewer.
Put a Map in your App! MyMaps makes it easy for Java developers to add maps to Swing applications. With access to WMS, Shapefile, Tiger and other free formats, you can add maps while avoiding the restrictive Terms of Use of those online mapping sites.