Dear Dick, Thank you very much for your reply.
I am going to consider what you suggested. And, I will keep updated this thread. Best Regards, Carlo ________________________________________ From: Joint <[email protected]> Sent: Tuesday, March 1, 2016 6:20 PM To: [email protected] Subject: Re: querying a SPARQL endpoint As an aside if there is an issue with the end point you could try emailing Chris Gutteridge as it's likely he will have had something to do with it... Dick -------- Original message -------- From: "Carlo.Allocca" <[email protected]> Date: 01/03/2016 3:54 pm (GMT+00:00) To: [email protected] Subject: querying a SPARQL endpoint Dear All, I am using Jena to query a SPARQL endpoint but I got "==== No variables ====" as result. But, when I run the same query over the SPARQL endpoint, I get the expected results. Below, I reported the details of the query, sparql endpoint and jena code. I tried to check other endpoints, but I got the same experience. What am I doing wrong? Any help to make it right? Many Thanks, Best Regards, Carlo === Query Southampton SPARQL endpoint 1) SPARQL EndPoint: String sparqlEndPoint = "http://sparql.data.southampton.ac.uk/";; 2) SPARQL Query: String qString3 = "prefix rdfs:<http://www.w3.org/2000/01/rdf-schema#> " + "prefix rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> " + " SELECT DISTINCT ?o where " + "{ " + " ?s ?prop ?o . " + " FILTER (isLiteral(?o)) " + "} LIMIT 1000"; 3) Jena code: QueryExecution qexec = QueryExecutionFactory.sparqlService(sparqlEndPoint, qString3, ""); qexec.setTimeout(10 * 60 * 1000); //10 min ResultSet results = qexec.execSelect(); ResultSetFormatter.out(out, results); 4) Jena Result: ==== No variables ==== ---- | | ==== 5) SPARQL endpoint Results: http://www.w3.org/2000/01/rdf-schema#label http://www.w3.org/2004/02/skos/core#prefLabel http://www.w3.org/2000/01/rdf-schema#label http://www.w3.org/2004/02/skos/core#prefLabel http://www.w3.org/2000/01/rdf-schema#comment http://www.w3.org/2000/01/rdf-schema#label http://www.w3.org/2004/02/skos/core#prefLabel http://www.w3.org/2000/01/rdf-schema#comment http://www.w3.org/2000/01/rdf-schema#label http://www.w3.org/2004/02/skos/core#prefLabel
