Hi Nico, You should pose this question on the Virtuoso Users mailing list rather than the DBpedia mailing, thus please subscribe the the Virtuoso mailing lists as detailed at:
http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VOSMailingLists What Virtuoso release are you running when encountering this issue ? We also have a Jena Provider which is Java based, but would like to determine if their is an issue with the Sesame provider and resolve it, so if you can provide steps to reproduce that would be useful ... Best Regards Hugh Williams Professional Services OpenLink Software Web: http://www.openlinksw.com Support: http://support.openlinksw.com Forums: http://boards.openlinksw.com/support Twitter: http://twitter.com/OpenLink On 20 Apr 2010, at 15:27, N.Stieler wrote: > Hello everybody, > > We have a problem with Virtuoso Sesame Provider. > > We get a NullPointerException, when we try to read the result > (result.hasnext()), but only if we have a OPTIONAL in the query: > SELECT distinct ?c ?l WHERE {{?c rdf:type owl:Class}. OPTIONAL {?c rdfs:label > ?l}. FILTER (isURI(?c)) } à Nullpointerexception > > SELECT distinct ?c ?l WHERE {{?c rdf:type owl:Class. FILTER (isURI(?c)) } à > exact result and no exceptions > > But if I run this query with using the Virtuoso JDBC Driver or web interface > it works in all cases. > > - Do you have a solution to this problem? > - Is it dependent to the OPTIONAL? > - Do you know any other Interfaces for Java? > > Thank you for your help. > > Regards, > Nico > > > -- > The Open University is incorporated by Royal Charter (RC 000391), an exempt > charity in England & Wales and a charity registered in Scotland (SC 038302). > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev_______________________________________________ > Dbpedia-discussion mailing list > dbpedia-discuss...@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion