code: private boolean evalClass(QueryImpl query,
                                QueryAtomGroupImpl group,
                                QueryResultImpl result,
                                QueryBindingImpl binding, QueryAtom atom) throws QueryEngineException {
          QueryArgument clsArg = atom.getArguments().get(0);
          if (!clsArg.isVar()) {
              return false;
          }
          BoundChecking boundChecking;
          // Need to check this but I think that if the variable is not bound then there's no need to recheck solutions
          Set<OWLClass> candidates = getClasses();
          return bindAndEvalClassCandidates(query, group, result, binding, clsArg, candidates, BoundChecking.DO_NOT_CHECK_BOUND);
      }
docs: Finds solutions to Class(?x)