Multiple statements can be created and used on the same connection, but only one resultset at once can be created and used on the same statement. If you create/open another one by the same statement, then any previously opened resultset will be implicitly closed, leading to "ResultSet closed" exceptions on any attempt to access it.

   As far as I know only one ResultSet can be created per statement, not per connection. This is supported by the : 'By default, only one ResultSet object per Statement object can be open at the same time. Therefore, if the reading of one ResultSet object is interleaved with the reading of another, each must have been generated by different Statement objects.' –