In WebSphere Application Server, the EJB Timer Service implements EJB Timers as a new kind of Scheduler Service task. By default, an internal (or pre-configured) scheduler instance is used to manage those tasks, and they are persisted to a Cloudscape database associated with the server process.
However, you can perform some basic customization to the internal scheduler instance. For information about how to do this customization, see Configuring a Timer Service .
Creation and cancellation of Timer objects are transactional and persistent. That is, if a Timer object is created within a transaction and that transaction is later rolled back, the Timer object's creation is rolled back as well. Similar rules apply to the cancellation of a Timer object. Timer objects also survive across application server shutdowns and restarts.