What is with GWT, AWT and SWING ?

So you have experienced Panels, Widgets and Event Listeners in AWT and Swing. And found the concept is pretty much similar in GWT as well. The differrence comes with the intent - Think of GWT and think of Javascript and HTML as Assembly language and GWT as a sort of High level language which generates Javascript and HTML.

Moreover, AWT/Swing are used for desktop Java apps or applets and both require JVM to run as opposed to GWT that is targeted for building web apps that run on browsers and are look-alike of desktop apps