http://www.gnu.org/software/java/java-software.html - Loads of Java Software, free, dunno if its possible to get it to work on a snap server.
Also this for developing Java -
http://www.gnu.org/software/java/developing-java.html
http://www.gjt.org/ is another link
http://www.keystonelearning.com/pdf/KLL_Brochure.pdf - What we want to do/ Snap Server Training