import java.awt.*;
import java.applet.*;
import java.util.*;

public class BorderLayoutDemo extends Applet
{
public void init()
{
setLayout(new BorderLayout());

add(new Button("This is arross the top"),
BorderLayout.NORTH);
add(new Label("The message is on the bottom"),
BorderLayout.SOUTH);
add(new Button("Left"),BorderLayout.WEST);
add(new Button("Right"),BorderLayout.EAST);
String message="This is the message in the Center!";
add(new TextArea(message),BorderLayout.CENTER);
}
}


编译通过，运行时出错：Exception in thread "main"java.lang.NoSuchMethodError:main
我是菜鸟，请高手指教一下