COMPONENTS OF A SYSTEM CAN CHANGE STATE and may need to inform other components that this change has happened . Java Beans and user -interface elements such as AWT or Swing objects use events to signal these changes. Jini also has an event mechanism, and this chapter looks at the distributed event model that is part of Jini. It looks at how remote event listeners are registered with objects, and how these objects notify their listeners of changes. Event listeners may disappear, and so the Jini event mechanism uses leases to manage listener lists.
This chapter also looks at how leases are managed by event sources. Finally, we'll look at how events can be used by applications to monitor when services are registered or discarded from service locators.