Question

After excecuting a query in sparql jena, I tried to get the query result as a list, so I used this:

res = ResultSetFormatter.toList(results);    

but when I write this method before that method the variable res returns null.

ResultSetFormatter.out(System.out, results);
res = ResultSetFormatter.toList(results);    

I don’t know what is the problem.

Answer 1

At a guess, I’d say ResultSetFormatter.out(ResultSet) consumes the ResultSet. So after this method has completed, ResultSet is empty.

It’s somewhat comparable to how an Iterator works: once you’ve iterated over all the elements, the iterator is empty.