The E4 Eclipse application uses events internally to manage the state of the user interface. The decoupling allows the user interface mechanisms to be separated from the user interface renderer, which allows different user interfaces to be presented (such as JavaFX).

There is an E4-specific wrapper for the EventAdmin service called the IEventBroker. This provides a simple mechanism to post or send objects to a particular topic, as well as frontends to register event listeners. It has specific ties to E4 and is present in the UI package. Create a plug-in named com.packtpub.e4.advanced.event.e4.