Apache Jena
A free and open source Java framework for building Semantic Web and Linked Data applications.
RDF
RDF API
Interact with the core API to create and read Resource Description Framework (RDF) graphs. Serialise your triples using popular formats such as RDF/XML or Turtle.
ARQ (SPARQL)
Query your RDF data using ARQ, a SPARQL 1.1 compliant engine. ARQ supports remote federated queries and free text search.
OWL
Ontology API
Work with models, RDFS and the Web Ontology Language (OWL) to add extra semantics to your RDF data.
Inference API
Reason over your data to expand and check the content of your triple store. Configure your own inference rules or use the built-in OWL and RDFS reasoners.