By default, JDBC uses an operation mode called auto-commit. This means that every update to the database is immediately made permanent.
Any situation where a logical unit of work requires more than one update to the database cannot be done safely in auto-commit mode. If something happens to the application or the system after one update is made and before any other updates are made, the first change cannot be undone when running in auto-commit mode.
Because changes are instantly made permanent in auto-commit mode, there is no need for the application to call the commit method or the rollback method. This makes applications easier to write.
Auto-commit mode can be enabled and disabled dynamically during a connection's existence. Auto-commit is enabled in the following way, assuming that data source already exists:
Connection connection = dataSource.getConnection(); Connection.setAutoCommit(false); // Disables auto-commit.
If the auto-commit setting is changed in the middle of a transaction, any pending work is automatically committed. An SQLException is generated if auto-commit is enabled for a connection that is part of a distributed transaction.