Exception retrieving results in jena resultSet - jena

Question

I'm having some problems when querying DBpedia throught Jena. The exception is thrown when iterating over the resultSet in the nextSolution method. Here is the code:
ResultSet results = throwQuery(query);
ArrayList<Movies> movs = new ArrayList<Movies>();
//try {
while (results.hasNext()) {
try{
QuerySolution q = results.nextSolution();
Movies m = new Movies();
m.setUrl(q.get("film_url").toString());
RDFNode node = q.get("film_label");
// Set a default title
String title = "";
if (node != null) {
// We delete the "#en" part that indicates that the label is in
// english
title = node.toString();
int ind = title.indexOf("#en");
title = title.substring(0, ind);
}
m.setTitle(title);
node = q.get("image_url");
// Set a default image
String image = "http://4.bp.blogspot.com/_rY0CJheAaRM/SuYJcVOqKbI/AAAAAAAAA2Y/abClDm72TuY/s320/NoCoverAvailable.png";
if (node != null) {
// For some reason the image link retrieved from dbpedia is
// broken. Here we fix it
image = node.toString();
int ind = image.indexOf("common");
image = image.substring(0, ind) + "en" + image.substring(ind + 7);
}
m.setImageurl(image);
movs.add(m);
}
catch(Exception e){
System.err.println("Error catched: " + e.getMessage());
}
}
return movs;
Where throwQuery
private final static String SERVICE = "http://dbpedia.org/sparql";
private static ResultSet throwQuery(String q) {
Query qFactory = QueryFactory.create(q);
QueryExecution qe = QueryExecutionFactory.sparqlService(SERVICE, qFactory);
ResultSet results = null;
try {
results = qe.execSelect();
} catch (QueryExceptionHTTP e) {
System.out.println(e.getMessage());
System.out.println(SERVICE + " is DOWN");
} finally {
qe.close();
return results;
}
}
And the testing query
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
SELECT ?film_label ?image_url ?film_url
WHERE {
?film_url rdf:type <http://dbpedia.org/ontology/Film> .
OPTIONAL{
?film_url rdfs:label ?film_label
FILTER (LANG(?film_label) = 'en')
}
OPTIONAL{
?film_url foaf:depiction ?image_url
}
FILTER regex(str(?film_url), "hola","i")
}
ORDER BY ?film_url
When the program starts iterating, everything goes well until arrive to the value Nicholas Nickleby (2002 film) then I get this exception:
com.hp.hpl.jena.sparql.resultset.ResultSetException: XMLStreamException: Unexpected EOF in start tag
at [row,col {unknown-source}]: [67,116]
at com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.staxError(XMLInputStAX.java:539 )
at com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.hasNext(XMLInputStAX.java:236)
at client.DBPediaConnector.getMovie(DBPediaConnector.java:67)
at customServices.MoviesService.searchInsertMovie(MoviesService.java:48)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1052)
at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1124)
at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:5388)
at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:619)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)
at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:571)
at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doAround(SystemInterceptorProxy.java:162)
at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:144)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:861)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:800)
at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:370)
at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:5360)
at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:5348)
at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:214)
... 47 more
Caused by: com.ctc.wstx.exc.WstxEOFException: Unexpected EOF in start tag
at [row,col {unknown-source}]: [67,116]
at com.ctc.wstx.sr.StreamScanner.throwUnexpectedEOF(StreamScanner.java:677)
at com.ctc.wstx.sr.StreamScanner.loadMore(StreamScanner.java:1034)
at com.ctc.wstx.sr.StreamScanner.getNextChar(StreamScanner.java:785)
at com.ctc.wstx.sr.BasicStreamReader.nextFromTree(BasicStreamReader.java:2790)
at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1065)
at com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.getOneSolution(XMLInputStAX.java:435)
at com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.hasNext(XMLInputStAX.java:232)
... 71 more
Seems for me like an internal error from Jena, but I have no idea. Am I doing something wrong? How can I solve this?

Answer 1

Please give a complete, minimal example. This is quite long.
DBpedia is returning broken XML for the results, possibly because the query is taking a long time to execute and the timeout is triggered. It seems to be a moderately slow query.
Try adding &timeout=60000 to query URL of 'http://dbpedia.org/sparql&timeout=60000', if your version of Jena is new enough. This may not be long enough. There is a hard internal limit on dbpedia which can not be overridden.
Executing at a different time of day may also help.
It may also be because corrupt XML is being returned. Execute the query at the DBpedia UI and get the XML results to check this.