import java.awt.*;
    import java.awt.event.*;
    
    class ButtonHolder {
      int m,n;
      Button b;
      
      
      ButtonHolder() {
        b = new Button( "hello" );
        b.setSize(30,30);
        addOneListener();
        addOneListener();
        }
    
      void addOneListener() {
          
        b.addActionListener( 
          new ActionListener() {
            int n=0;
            public void actionPerformed(ActionEvent e) {
              ++n;
              ++m;  
              b.setLabel(   "m = " + m
                        + ", this.n = " + this.n );
              //b.redraw();
              }
            } );
            
          }
        
    
      // Now, imagine you make three new ButtonHolder()s,
      // and each ButtonHolder makes two of these anonymous inner classes.
      // How many n's?  How many m's?
      // Note that the instance of the ActionListeners are not fields
      // of ButtonHolder; their <em>closure</em> does include fields of ButtonHolder, though.
      // Also note that other parts of code (e.g. the awt event handler)
      // has references to the ActionListener, even though ButtonHolder() is not in its scope.

      
      
      
      
      
      
   public static void main(String[] args) throws InterruptedException {
       Frame f = new Frame();
       ButtonHolder bh1 = new ButtonHolder();
       ButtonHolder bh2 = new ButtonHolder();
       
       f.setSize( 100, 100 );
       f.add( bh1.b );
       f.add( bh2.b );
       f.setVisible(true);
       Thread.sleep(8000);
       System.out.println(   "bh1.m = " + bh1.m 
                         + ", bh1.n = " + bh1.n 
                         + ", bh2.m = " + bh2.m 
                         + ", bh2.n = " + bh2.n 
                         );
       }
      
      
      }