title: how to use constant field values defined in predefined classes
body: <p>My question is how to use constant  field values defined in predefined classes like I am practicing on the events program, and currently on action event, I have understand
  the action listener part but when I go to action event part , I don't know how to use the static field constant, only I am able to use methods of the that classes, it will be more helpful if a simple example is given by you (simple not complex)</p>
  
  <p>Elaboration:</p>
  
  <p>I want to know how to use the ALT_MASK, ACTION_FIRST, ACTION_LAST constant
  Also please show me how to create events of my own</p>