This week's book giveaway is in the OCAJP forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide 1Z0-808 and have Jeanne Boyarsky & Scott Selikoff on-line! See this thread for details.
executeUpdate() is special form of execute(), that only performs DML Operations, while execute() performs any SQL Operation within the limitations of the support of database driver being used. That's why executeUpdate() returns int - No. of rows affected, while execute() returns boolean depending on the previous operation performed.