The J2EE™ Tutorial Second Edition

Using the Timer Service

Applications that model business work flows often rely on timed notifications. The timer service of the enterprise bean container enables you to schedule timed notifications for all types of enterprise beans except for stateful session beans. You can schedule a timed notification to occur at a specific time, after a duration of time, or at timed intervals. For example, you could set timers to go off at 10:30 AM on May 23, in 30 days, or every 12 hours.

When a timer expires (goes off), the container calls the ejbTimeout method of the bean's implementation class. The ejbTimeout method contains the business logic that handles the timed event. Because ejbTimeout is defined by the javax.ejb.TimedObject interface, the bean class ...