RDF and Java

Using rdf2java (of course) you can convert RDF to Java objects and back again:
http://www.dfki.uni-kl.de/frodo/rdf2java/

To validate against a schema you could use:
http://sourceforge.net/projects/sesame/
http://www.ics.forth.gr/proj/isst/RDF/
http://www.daml.org/validator/

Also, the KOAN people have some recent publications about SEAL (Semantic Portal):

http://www.aifb.uni-karlsruhe.de/WBS/Publ/pub2002.html