Apache Jena is an open-source Java framework for building Semantic Web and Linked Data applications. Its RDF API reads and writes graphs in formats such as RDF/XML and Turtle. The TDB component is a native triple store, Fuseki exposes stored data as a SPARQL endpoint over HTTP, and the ARQ engine runs SPARQL 1.1 queries, including federated queries. Ontology and inference APIs support reasoning with RDFS and OWL. Developers embed Jena in their own applications or run Fuseki as a server.
Jena is maintained by the Apache Software Foundation, a US 501(c)(3) non-profit, and is released under the Apache License 2.0. The software runs on infrastructure the organisation chooses, and the data it processes stays where that organisation deploys it. For a European organisation this means control over location and access. The foundation's US status concerns the governance of the project, not the data the software processes. Jena is an alternative to proprietary triple stores and commercial semantic-web platforms, without vendor lock-in; operation, updates and security remain the organisation's responsibility.