[자바] 간단한 프로그램인데...

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

public class SimpleAnimation 
{
	int x = 70;
	int y = 70;

	public static void main(String[] args)
	{
		SimpleAnimation gui = new SimpleAnimation();
		gui.go();
	}

	public void go()
	{
		JFrame frame = new JFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		MyDrawPanel drawPanel = new MyDrawPanel();

		frame.getContentPane().add(drawPanel);
		frame.setSize(300, 300);
		frame.setVisible(true);

		for (int i = 0; i < 130; i++) 
		{
			x++;
			y++;

			drawPanel.repaint();

			try
			{
				Thread.sleep(50);
			}
			catch(Exception ex)
			{
			}
		}

		class MyDrawPanel extends JPanel
		{
			public void paintComponent(Graphics g)
			{
				g.setColor(Color.white);
				g.fillRect(0, 0, this.getWidth(), this.getHeight());
				g.setColor(Color.green);
				g.fillOval(x, y, 40, 40);
			}
		    
		}
    }
};

간단하게 애니메이션 비슷하게 만들어볼려고 내부클래스를 써서 했는데 컴파일 에러가 나네요.

MyDrawPanel drawPanel = new MyDrawPanel();
에서 에러가 나는데...뭐가 틀린거죠? 도통 모르겠네요;;