Event dispatching thread: Difference between revisions

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The '''event dispatching thread''' (EDT) is a background [[Thread (computer sciencecomputing)|thread]] used in [[Java (programming language)|Java]] to process events from the [[Abstract Window Toolkit]] (AWT) [[graphical user interface]] [[event queue]]. It is an example of the generic concept of [[event-driven programming]], that is popular in many other contexts than Java, for example, [[web browser]]s, or [[web server]]s.

The events are primarily update events that cause user interface [[Software componentry|components]] to redraw themselves, or input events from [[input device]]s such as the mouse or keyboard. The AWT uses a single-threaded painting [[Model (abstract)|model]] in which all screen updates must be performed from a single thread. The event dispatching thread is the only valid thread to update the visual state of visible user interface components. Updating visible components from other threads is the source of many common [[Software bug|bugs]] in Java [[Computer program|programs]] that use [[Swing (Java)|Swing]].<ref>This problem is not specific to Java [[Swing (Java)|Swing]]. There is the same issue in most [[Widget toolkit]]s, as for example [[Windows Forms]], where the [[BackgroundWorker]] class performs the same purpose as [[SwingWorker]] in Java.</ref> The event dispatching thread is called the '''primordial worker''' in [[Adobe Flash]] and the '''UI thread''' in [[Standard Widget Toolkit|SWT]], [[.NET Framework]] and [[Android (operating system)|Android]].