John Zukowski puts his finger on it in this article. While tracing Swing’s single-threaded event model from Java 1.0 to its origins in the JavaBeans component model and AWT, he reveals an ...

Within Java, both AWT (Abstract Window Toolkit) and Swing are based on an event model. Java provides the classes EventQueue, AWTEvent, AWTEventMultiCaster, and EventListener in the java.awt package.