Github user LosD commented on the issue:
https://github.com/apache/metamodel/pull/205
D'oh, I missed that it was in JDBC, then the Excel issue is unrelated for
sure. :-)
In theory, we shouldn't need to close the resultset, as resultsets are
supposed to close along with the statements, but drivers can probably easily
break that convention, so it's a good thing to ensure the closure in our end.---
