Variable name might be wrong for the convert method of the OWLClassExpressionToSPARQLConverter class.

[yayamamo]

Even though the second argument of the convert method of the OWLClassExpressionToSPARQLConverter class is like "?s", the following exception occurs. It might be due to the variable name of the method is "String rootVariable" whereas the one in the createSelectClause method is "Stack variables". If not, could you let me know why this exception occurs? I use 0.1-SNAPSHOT of owl2sparql-core.

Exception in thread "main" java.util.NoSuchElementException
	at java.util.Vector.firstElement(Vector.java:489)
	at org.aksw.owl2sparql.OWLClassExpressionToSPARQLConverter.createSelectClause(OWLClassExpressionToSPARQLConverter.java:343)
	at org.aksw.owl2sparql.OWLClassExpressionToSPARQLConverter.convert(OWLClassExpressionToSPARQLConverter.java:125)
...