This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
Lots of ways; doing a search of these fora will reveal other threads about the same subject. Try a java.util.Timer or a javax.swing.Timer, or repeatedly querying Calender objects for the time, or anacron or cron, or Windows task scheduler. As I said, a search will reveal many possible solutions.