Error in query

[javed khan]

Hello

What is the problem in this query: 'Male' is string literal here. (The
query works inside Protege)

CONSTRUCT   { ?x mo:hasUncle ?y } WHERE { ?x  mo:hasParents ?z .?z
mo:Gender  'Male' . ?z mo:hasBrother ?y}

Query query = QueryFactory.create(str);
QueryExecution qexec = QueryExecutionFactory.create(query, model) ;
ResultSet results = (ResultSet) qexec.execConstruct() ;
        while (results.hasNext())
{
QuerySolution binding = results.nextSolution();
                Literal lit =  binding.get("z").asLiteral();