帮忙看下实现菱形按钮的代码错误？
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;

public class TestButton extends JButton {
JFrame f;

JButton0 b0;

Image img;

JButton b;

ImageIcon ii;

public TestButton() {
init();
}

public void init() {

img = Toolkit.getDefaultToolkit().getImage(
TestButton.class.getResource( "1.jpg "));
ii = new ImageIcon(img);
f = new JFrame( "test ");
b0 = new JButton0( "OK ", img);

f.add(b0);
b0.setBounds(100, 100, 100, 100);
b0.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent arg0) {
JOptionPane.showMessageDialog(f, "hehe！ ");
}

});
f.setLayout(new FlowLayout());
f.setSize(400, 400);
f.setVisible(true);

}

public static void main(String args[]) {
new TestButton();
}

}

class JButton0 extends JButton {

Image img;

String text;

public JButton0() {
this.setSize(100, 100);
}

public JButton0(Image img) {
this.img = img;
}

public JButton0(Icon icon) {
this.setIcon(icon);
}

public JButton0(String text) {
this.text = text;
}

public JButton0(String text, Image img) {
this.text = text;
this.img = img;
}

public void paint(Graphics g) {
int[] x = { 0, 50, 100, 50 };
int[] y = { 50, 0, 50, 100 };
g.drawPolygon(x, y, 4);
g.setColor(Color.blue);
g.fillPolygon(x, y, 4);
if (img != null) {
g.drawImage(img, 25, 25, this.getHeight() / 2, this.getWidth() / 2,
this);
}
g.setColor(Color.RED);
g.drawString(text, 43, 55);
}
}
在eclipse
运行错误提示
Uncaught error fetching image:
java.lang.NullPointerException
at sun.awt.image.URLImageSource.getConnection(URLImageSource.java:97)
at sun.awt.image.URLImageSource.getDecoder(URLImageSource.java:106)
at sun.awt.image.InputStreamImageSource.doFetch(InputStreamImageSource.java:240)
at sun.awt.image.ImageFetcher.fetchloop(ImageFetcher.java:172)
at sun.awt.image.ImageFetcher.run(ImageFetcher.java:136)

高手们帮忙改下？？谢谢各位？

[解决办法]
img = Toolkit.getDefaultToolkit().getImage(

TestButton.class.getResource( "1.jpg ")); // 没读出图片来
或者用
ImageIcon icon = new ImageIcon(this.getClass().getClassLoader().getResource( "1.jpg "));