ASK
{
	?cat  wdt:P31 wd:Q146 . 
  	?cat wdt:P570 ?d .
	SERVICE wikibase:label { bd:serviceParam wikibase:language "en" }
}

Caused by: java.lang.NullPointerException
	at org.wikidata.query.rdf.blazegraph.label.EmptyLabelServiceOptimizer.addResolutions(EmptyLabelServiceOptimizer.java:77)
	at org.wikidata.query.rdf.blazegraph.label.EmptyLabelServiceOptimizer.optimizeJoinGroup(EmptyLabelServiceOptimizer.java:66)
	at com.bigdata.rdf.sparql.ast.optimizers.AbstractJoinGroupOptimizer.optimize(AbstractJoinGroupOptimizer.java:161)
	at com.bigdata.rdf.sparql.ast.optimizers.AbstractJoinGroupOptimizer.optimize(AbstractJoinGroupOptimizer.java:101)
	at com.bigdata.rdf.sparql.ast.optimizers.ASTOptimizerList.optimize(ASTOptimizerList.java:126)
	at com.bigdata.rdf.sparql.ast.eval.AST2BOpUtility.convert(AST2BOpUtility.java:267)
	at com.bigdata.rdf.sparql.ast.eval.ASTEvalHelper.evaluateBooleanQuery(ASTEvalHelper.java:156)
	at com.bigdata.rdf.sail.BigdataSailBooleanQuery.evaluate(BigdataSailBooleanQuery.java:77)
	at com.bigdata.rdf.sail.BigdataSailBooleanQuery.evaluate(BigdataSailBooleanQuery.java:59)
	at com.bigdata.rdf.sail.webapp.BigdataRDFContext$AskQueryTask.doQuery(BigdataRDFContext.java:1645)
	at com.bigdata.rdf.sail.webapp.BigdataRDFContext$AbstractQueryTask.innerCall(BigdataRDFContext.java:1568)
	at com.bigdata.rdf.sail.webapp.BigdataRDFContext$AbstractQueryTask.call(BigdataRDFContext.java:1533)
	at com.bigdata.rdf.sail.webapp.BigdataRDFContext$AbstractQueryTask.call(BigdataRDFContext.java:705)