ARQ is a query engine for Jena that supports the SPARQL RDF Query language. SPARQL is the query language developed by the W3C RDF Data Access Working Group.
Features of ARQ that were formally ARQ extensions but are now legal SPARQL 1.1:
Features of ARQ that are legal SPARQL syntax.
Feature of ARQ that go beyond SPARQL syntax. The default query
language is standard SPARQL. These features require the query to be
parsed with an explicit declaration of
ARQ supports the W3C standard SPARQL Update language as well as the precursor submission to W3C. Using the standard is preferred; support for the submission is for legacy use.
Articles and documentation elsewhere:
Online Query Form for experimenting with SPARQL queries.