The following must be considered when using the ResultSet interface:

• Before reading any values, you must call next(). This returns true if there is a result, but more importantly, it prepares the row for processing.
• You must close a ResultSet by calling close() once you have finished using it.
• Once you make another query with the Statement used to create a ResultSet, the currently open ResultSet instance is closed automatically.
• When PreparedStatement API is used, ResultSet switches to binary mode after five query executions (this default is set by the prepareThreshold connection property, see Server Prepared Statements). This may cause unexpected behavior when some methods are called. For example, results on method calls such as getString() on non-string data types,
  while logically　equivalent, may be formatted differently after execution exceeds the set prepareThreshold when conversion to object method switches to one matching the return mode.