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1 Reply Latest reply: Jul 23, 2012 9:26 PM by alwu RSS

NullPointerException while executing SPARQL through Jena

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Hi,

I was trying to execute a SPARQL through Jena API. I am getting the following exception when invoking the "ResultSetFormatter.out(System.out, results);" method. Any idea why this happens ? Appreciate any help on this.


I connect to Oracle using the following Jena code
============================================
Oracle oracle = new Oracle(szJdbcURL, szUser, szPasswd);
Model model = ModelOracleSem.createOracleSemModel(
oracle, szModelName);
==============================================

This is the exception I am getting.

java.lang.NullPointerException
     at oracle.spatial.rdf.client.jena.OracleRepeatApply.nextStage(OracleRepeatApply.java:794)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIterRepeatApply.makeNextStage(QueryIterRepeatApply.java:101)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIterRepeatApply.hasNextBinding(QueryIterRepeatApply.java:53)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:86)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIterProcessBinding.hasNextBinding(QueryIterProcessBinding.java:49)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:86)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIterConvert.hasNextBinding(QueryIterConvert.java:54)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:86)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIterConvert.hasNextBinding(QueryIterConvert.java:54)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:86)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIterDistinctReduced.hasNextBinding(QueryIterDistinctReduced.java:42)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:86)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorWrapper.hasNextBinding(QueryIteratorWrapper.java:30)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:86)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorWrapper.hasNextBinding(QueryIteratorWrapper.java:30)
     at com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorBase.hasNext(QueryIteratorBase.java:86)
     at com.hp.hpl.jena.sparql.engine.ResultSetStream.hasNext(ResultSetStream.java:57)
     at com.hp.hpl.jena.sparql.resultset.ResultSetMem.<init>(ResultSetMem.java:82)
     at com.hp.hpl.jena.sparql.resultset.TextOutput.write(TextOutput.java:133)
     at com.hp.hpl.jena.sparql.resultset.TextOutput.write(TextOutput.java:116)
     at com.hp.hpl.jena.sparql.resultset.TextOutput.write(TextOutput.java:104)
     at com.hp.hpl.jena.sparql.resultset.TextOutput.format(TextOutput.java:51)
     at com.hp.hpl.jena.query.ResultSetFormatter.out(ResultSetFormatter.java:96)
     at com.hp.hpl.jena.query.ResultSetFormatter.out(ResultSetFormatter.java:48)

Thanks
Mahesh

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