VIVO is a semantic web project built on the Jena semantic web framework, and is an application to facilitate the discovery of researchers and collaborators across the country and internationally.
foaf4java - Based on the Jena Semantic Web framework (http://jena.sourceforge.net), “FOAF for Java” is a toolkit for handling FOAF profiles easily, by Safelayer (http://labs.safelayer.com). Find more details about FOAF at http://xmlns.com/foaf/spec/.
NG4J - 'Named Graphs API for Jena' is an extension to the Jena Semantic Web framework for parsing, manipulating and serializing sets of Named Graphs. For details about Named Graphs see http://www.w3.org/2004/03/trix/
Makna is a semantic wiki implementation. It is an extension of the wiki engine JSPWiki with the semantic web framework Jena. The aim is to bring together the best of two worlds - the simplicity of wiki systems and the power of semantic web technologies.
PRE4J (Partial RDF Encryption API for Jena) is a lightweight API for encrypting selected RDF graph elements. PRE4J provides cryptographic extensions to the Jena Semantic Web Framework.