Java toolkit for manipulating RDF models from HP Labs Bristol
    
    
      - 
        ARP - RDF/XML Parser
      
- 
        Persistence - MySQL, Oracle and Postgres
      
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        Ontology Subsystem - API for managing RDF, RDFS, OWL
      
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        Reasoning Subsystem - Inference capabilities for RDFS and
        OWL
      
- 
        RDQL query language
      
      Jena is powerful, flexible and easy Java based toolkit for
      developing applications within the Semantic Web.