PoundstoKilogramsGUI.java

      import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class PoundstoKilogramsGUI
{
   private int WIDTH = 300;
   private int HEIGHT = 75;

   private JFrame frame;
   private JPanel panel;
   private JLabel inputLabel, outputLabel, resultLabel;
   private JTextField pounds;

   public PoundstoKilogramsGUI(String title, String label1, String label2)
   {
      frame = new JFrame (title);
      frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);

      inputLabel = new JLabel (label1);
      outputLabel = new JLabel (label2);
      resultLabel = new JLabel ("---");

      pounds = new JTextField (5);
      pounds.addActionListener (new TempListener());

      panel = new JPanel();
      panel.setPreferredSize (new Dimension(WIDTH, HEIGHT));
      panel.setBackground (Color.yellow);
      panel.add (inputLabel);
      panel.add (pounds);
      panel.add (outputLabel);
      panel.add (resultLabel);

      frame.getContentPane().add (panel);
   }
   public void display()
   {
      frame.pack();
      frame.setVisible(true); // book has old version
   }

   private class TempListener implements ActionListener
   {
      public void actionPerformed (ActionEvent event)
      {
         Double poundsTemp, kilogramsTemp;

         String text = pounds.getText();

         poundsTemp = Double.parseDouble(text);
         kilogramsTemp = poundsTemp / 2.2 ;

         resultLabel.setText (Double.toString (kilogramsTemp));
      }
   }
}

MyClassTest.java

      import java.util.*;
public class MyClassTest
{
	public static void main(String[] args)
	{
		MyClass object1 = new MyClass("sam");
		MyClass object2 = new MyClass("bruce");
		MyClass object3 = new MyClass("fred");
		
		MyClass[] list = {object1, object2, object3};
		
		for(int i = 0; i < list.length; i++)
			System.out.println(list[i]);
			
		ArrayList alist = new ArrayList();
		
		alist.add(object1);
		alist.add(object2);
		alist.add(object3);
		
		Iterator it = alist.iterator();
		
		while(it.hasNext())
		{
			System.out.println(it.next());
		}
	
		System.out.println("There are " + MyClass.getCount() + " objects.");
	}
}

MyClass.java

      public class MyClass
{
	private String name;
	private static int count;
	
	public MyClass()
	{
		count++;
	}
	
	public MyClass(String name)
	{
		this.name = name;
		count++;
	}
	
	public void setName(String name)
	{
		this.name = name;
	}
	
	public String getName()
	{
		return name;
	}
	
	public String toString()
	{
		return name;
	}
	public static int getCount()
	{
		return count;
	}
	
}
	
	

Dog.java

      public class Dog implements Animal {
    private String name;

    public Dog() {
    }

    public Dog(String name) {
        this.name = name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public String toString() {
        return name;
    }

    public void speak() {
        System.out.println("bow wow");
    }
}

Animal.java

      public interface Animal
{
 public void speak();
}