import java.awt.*;
import java.awt.event.*;

public class ButtonHolder {
  private int m,n;
  Button b;
  
  
  ButtonHolder() {
    b = new Button();
    addOneListener();
    addOneListener();
    }

  void addOneListener() {
      
    b.addActionListener( 
      new ActionListener() {
        int n=0;
        public void actionPerformed(ActionEvent e) {
          ++n;
          ++m;
          }
        } );
        
      }
    

  // 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.
  }