How to covert Gauss-Kruger coordinates to UTM coordinates with GeoTools java library? As I have figured out the location (zone, country) is important. I need the calculation for Slovenia.
There is example code on using the GeoTools CRS module at http://docs.geotools.org/stable/userguide/examples/crslab.html which shows how to make the transformation if you know the EPSG codes of the two projections you want to use.
If you don't know the EPSG codes then you can look them up at http://spatialreference.org, if however the code you want doesn't have an EPSG code then you will need to look at http://docs.codehaus.org/display/GEOTDOC/01+CRS+Helper+Class to find an example of how to build a CRS from a WKT string (available from http://spatialreference.org or your shapefiles .prj file).