JAMS & Components:
Sven Kralisch, Peter Krause, Christian Fischer, 
Manfred Fink, Robert Riedel, Christin Michel, 
Ronny Berndt and many others

Libraries:
Apache Commons (http://commons.apache.org)
GeoTools (http://www.geotools.org)
GeoAPI (http://www.geoapi.org)
JTS Topology Suite (http://www.vividsolutions.com/jts)
Gluegen (http://jogamp.org/gluegen/www)
JOGL (http://jogamp.org/jogl/www)
JScience (http://jscience.org)
JFreeChart (http://www.jfree.org/jfreechart)
H2 Database (http://www.h2database.com)   
JAMA (http://math.nist.gov/javanumerics/jama)  
TROVE (http://trove.starlight-systems.com)
JUEL (http://juel.sourceforge.net)
WorldWind (http://worldwind.arc.nasa.gov)
... and many others
                                                       