Jena 2 Preview 2 Released the changes since preview 1 include:

* RDQL: support for datatyped literals and standard namespace prefixes
* N3: support for datatyped literals
* I/O: bugfixes and reflecting latest WG decisions
* Reification: new WG-compatible API, I/O round-tripping
* Ontology API: preliminary release of generic API for OWL and DAML+OIL; with improved ontology document management. Inferencing limited to class/property hierarchy closure.

The preview can be downloaded from: http://prdownloads.sourceforge.net/jena/Jena-2p2.zip?download. The Jena Roadmap was also recently made available.