Accessing Surrounding Variables

• The actionPerformed method can access variables from the surrounding scope, like this:

  public static void main(String[] args)
  {
     . . .
     final Rectangle box = new Rectangle(5, 10, 20, 30);
  
     class Mover implements ActionListener
     {
        public void actionPerformed(ActionEvent event)
        {
           // Move the rectangle
           box.translate(1, 1);
        }
     }
     . . .
  }

• Local variables that are accessed by an inner-class method must be declared as final
• Inner class can access fields of surrounding class that belong to the object that constructed the inner class object
• An inner class object created inside a static method can only access static surrounding fields