This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Commit applies your update, insert or delete transactions to the database, and makes these transactions available for all users. In the most simple form, if you want to use transactions in JDBC: You turn off your connection's auto commit functionality. You perform your update queries (update, insert delete). You do a commit by calling your database connection's commit().