What is the error in code

[kumar rohit]

import java.io.InputStream;

import com.hp.hpl.jena.ontology.OntDocumentManager;
import com.hp.hpl.jena.ontology.OntModel;
import com.hp.hpl.jena.ontology.OntModelSpec;
import com.hp.hpl.jena.query.Query;
import com.hp.hpl.jena.query.QueryExecution;
import com.hp.hpl.jena.query.QueryExecutionFactory;
import com.hp.hpl.jena.query.QueryFactory;
import com.hp.hpl.jena.query.ResultSet;
import com.hp.hpl.jena.query.ResultSetFormatter;
import com.hp.hpl.jena.rdf.model.ModelFactory;
import com.hp.hpl.jena.util.FileManager;


public class famtree {
static final String inputfile =("C://Users//asad
ali//Desktop//Project//protege//relation.owl");

public static void main(String[] args) {
OntDocumentManager mgr=new OntDocumentManager();

OntModelSpec spec=new OntModelSpec(OntModelSpec.OWL_DL_MEM);

spec.setDocumentManager(mgr);

OntModel m = ModelFactory.createOntologyModel(spec,null);

InputStream in=FileManager.get().open(inputfile);
if (in==null)
{
throw new IllegalArgumentException("File" + inputfile + "not found");
}
m.read(in,"");

String querystring="PREFIX ss:<http://www.semanticweb.org"; +"SELECT ?x" +
"WHERE {" + "?x ss:hasson ss:zia" + "}";

Query query=QueryFactory.create(querystring);

QueryExecution qe = QueryExecutionFactory.create(query, m);

ResultSet results = qe.execSelect();

ResultSetFormatter.out(System.out, results, query);

qe.close();
}
}

The following error displays in Eclipse
___________________________________

Exception in thread "main" com.hp.hpl.jena.query.QueryParseException:
Encountered " "<" "< "" at line 1, column 11.
Was expecting:
    <IRIref> ...

at
com.hp.hpl.jena.sparql.lang.ParserSPARQL11.perform(ParserSPARQL11.java:102)
at com.hp.hpl.jena.sparql.lang.ParserSPARQL11.parse$(ParserSPARQL11.java:53)
at com.hp.hpl.jena.sparql.lang.SPARQLParser.parse(SPARQLParser.java:34)
at com.hp.hpl.jena.query.QueryFactory.parse(QueryFactory.java:148)
at com.hp.hpl.jena.query.QueryFactory.create(QueryFactory.java:80)
at com.hp.hpl.jena.query.QueryFactory.create(QueryFactory.java:53)
at com.hp.hpl.jena.query.QueryFactory.create(QueryFactory.java:41)
at familytree.famtree.main(famtree.java:37)