How Transactions Are Autocommitted
Application developers must be aware that the DBMS Server imposes severe limits on the operations that can be performed when autocommit is enabled (the JDBC default transaction mode) and a cursor is opened. In general, only one cursor at a time can be open during autocommit, and only cursor-related operations (cursor delete, cursor update) can be performed. Violating this restriction results in an exception being thrown with the message text:
No MST is currently in progress, cannot declare another cursor
Cursors are opened by the Statement and PreparedStatement executeQuery() methods and remain open until the associated ResultSet is closed. The driver closes a cursor automatically when the end of the result set is reached, but applications must not rely on this behavior. JDBC applications can avoid many problems by calling the close() method of each JDBC object when the object is no longer needed.