Managing & Using MySQL, 2nd Edition

Error Handling and Clean Up

All JDBC method calls can throw SQLException or one of its subclasses if something happens during a database call. Your code should be set up to catch this exception, deal with it, and clean up any database resources that have been allocated. Each of the JDBC classes mentioned so far has a close( ) method associated with it. Practically speaking, however, you only really need to make sure you close things whose calling processes might remain open for a while. In the examples we have seen so far, you only really need to close your database connections. Closing the database connection closes any statements and result sets associated with it automatically. If you intend to leave a connection open for any period of time, however, it is a good idea to close the statements you create using that connection when you finish with them. In the JDBC examples you have seen, this clean up happens in a finally clause. You do this since you want to make sure to close the database connection no matter what happens.