Principle of GUI Application

GUI Programs that we create in Java contains three tiers of software.

 Namely :-

• GUI components
• Event Listeners
• Event Handler

GUI components that makes up the GUI such as button, textbox, menus etc.. Whereas Event listeners are registered with GUI objects. In case of occurance of an event the object get notifies its event listener. The listener then invokes event handler method. The event handler method then executes the java code written in it.