JAvaインスタンス化コード----------------リスニングイベント

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

public class ButtonTest
{
	public static void main(String args[])
	{
		ButtonFrame frame = new ButtonFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}
}

class ButtonFrame extends JFrame
{
	public ButtonFrame()
	{
		setTitle("Button Test");
		setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
		
		
		ButtonPanel panel = new ButtonPanel();
		add(panel);
	}
	
	public static final int DEFAULT_WIDTH = 800;
	public static final int DEFAULT_HEIGHT = 500;
}

class ButtonPanel extends JPanel
{
	public ButtonPanel()
	{
		// button
		JButton yellowButton = new JButton("yellow");
		JButton blueButton = new JButton("blue");
		JButton redButton = new JButton("red");
		
		// button 
		add(yellowButton);
		add(blueButton);
		add(redButton);
	
		// 
		ColorAction yellowAction = new ColorAction(Color.YELLOW);
		ColorAction blueAction = new ColorAction(Color.BLUE);
		ColorAction redAction = new ColorAction(Color.RED);
		
		// 
		yellowButton.addActionListener(yellowAction);
		blueButton.addActionListener(blueAction);
		redButton.addActionListener(redAction);
	}

	private class ColorAction implements ActionListener
	{
		public ColorAction(Color c)
		{
			backgroundColor = c;
		}
		
		public void actionPerformed(ActionEvent event)
		{
			setBackground(backgroundColor);
		}
		
		private Color backgroundColor;
	}
}