大家帮我看看这段程序怎么了！谢谢！
import java.awt.*;
import java.io.*;
import javax.swing.*;

public class VideoCD extends JApplet{
JPanel panelObject;
int stopCount;
int startCount;

JLabel labelVideoCDNo,labelVideoCDName,labelGenre,labelArtist,labelCount;
JTextField textVideoCDNo,textVideoCDName,textArtist;
JComboBox comboGenre;

public void init(){
panelObject = new JPanel();
getContentPane().add(panelObject);

labelVideoCDNo = new JLabel( "VIdeo CD Number ");
labelVideoCDName = new JLabel( "Name ");
labelGenre = new JLabel( "Package ");
labelGenre = new JLabel( "Artist ");
labelCount = new JLabel();

textVideoCDNo = new JTextField(15);
textVideoCDName = new JTextField(30);
textArtist = new JTextField(30);

String genres[] = { "Rock ", "Pop ", "Classical ", "Rap "};
comboGenre = new JComboBox(genres);
panelObject.add(labelVideoCDNo);
panelObject.add(textVideoCDNo);
panelObject.add(labelVideoCDName);
panelObject.add(textVideoCDName);
panelObject.add(labelGenre);
panelObject.add(comboGenre);
panelObject.add(labelArtist);
panelObject.add(textArtist);
panelObject.add(labelCount);
startCount++;
String count = "Start count is "+ startCount + "Stop count is " + stopCount;
labelCount.setText(count);
stopCount++;
String count1 = "Stop Count is " + stopCount + "Start count is " + startCount;
labelCount.setText(count1);
}

}


运行的时候老是报下面这段错：
java.lang.NullPointerException
at java.awt.Container.addImpl(Unknown Source)
at java.awt.Container.add(Unknown Source)
at VideoCD.init(VideoCD.java:36)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

[解决办法]
labelArtist = new JLabel( "Whatever ");