Jena is an open source Semantic Web framework for Java. It provides an API to extract data from and write to RDF graphs. The graphs are represented as an abstract "model". A model can be sourced with data from files, databases, URLs or a combination of these. A Model can also be queried through SPARQL and updated through SPARUL.
Jena is similar to Sesame; though, unlike Sesame, Jena provides support for OWL (Web Ontology Language). The framework has various internal reasoners and also provides support for external reasoners through the DIG interface. In addition the Pellet reasoner (an open source Java OWL-DL reasoner) can be set up to work in Jena without using the DIG interface. This allows for improved speed and overcomes some of the limitations in the DIG protocol.
Jena supports serialisation of RDF graphs to:
Joseki is an RDF server. The goal of Joseki is to provide an HTTP interface to RDF data. It fully supports SPARQL for querying, but as of yet, it does not provide an update protocol. The project is a sub-project of Jena and is developed as a J2EE application. Joseki can also be run stand-alone server as it ships preconfigured with the Jetty web server.