On 28. August 2010 the Jena project celebrated its 10th year of providing us with a Semantic Web Framework, Jena now is probably one of the most popular Java RDF APIs in the community. It started as an idea by a developer at HPLabs in Bristol and Andy mentioned Brian McBride’s email (
http://lists.w3.org/Archives/Public/www-rdf-interest/2000Aug/0128.html ) as the official starting point for the project.
TDB is a persistent graph storage layer for Jena. TDB works with the Jena SPARQL query engine (ARQ) to provide complete SPARQL together with a number of extensions (e.g. property functions, aggregates, arbitrary length property paths). It is a pure-Java, employing memory mapped I/O, a custom implementation of B+Trees and optimized range filters for XSD value stapces (integers, decimals, dates, dateTime).