Creating an executable jar-file including a custom package

Question

I am trying to learn how to create executable jar-files. I have managed this with a single class. However having a class which is an extention of another class which in turn belongs to custom package, I can't make it work.Running the program normally is not a problem. I don't think the problem is the actual code, but I will include it here anyway. I create the jar-file using:
jar -cmf Direkt2b.txt Direkt2b.jar *.class
where Direkt2b.txt is just:
Main-Class: Diriekt2b
Only the main class-file is included this way. Copying the other file to the same directory before creation doesn't help either. There is no error messages, the jar-file just refuses to run no matter what.
The main-class:
import java.awt.*;
import extra.*;
class Direkt2b extends ExtendedFrame {
     Font f;
     Direkt2b() {
          f = new Font("SansSerif", Font.BOLD, 24);
          setBackground(Color.yellow);
          setSize(400,150);
     public void paint(Graphics g) {
          g.setFont(f);
          g.setColor(Color.blue);
          g.drawString("V?lkommen till Java Direkt", 45, 100);
     public static void main (String[] arg) {
          Direkt2b d2 = new Direkt2b();
          d2.setVisible(true);
The help-class:
package extra;
import java.awt.*;
import java.awt.event.*;
public class ExtendedFrame extends Frame {
     private static boolean first = true;
     private boolean isFirst = first;
     public ExtendedFrame() {
          addWindowListener(theListener);
          first=false;
     WindowAdapter theListener = new WindowAdapter () {
          public void windowClosing(WindowEvent e) {
          dispose();
          if (isFirst)
               System.exit(0);
}

Answer 1

My problem wasn't really getting more than one class in a jar-file,
but rather that my jar-file with multiple classes wouldn't execute.
Reading the original post I realized that maybe I was unclear about that.
However I have solved the problem now so for anybody reading this
thread in the future I will tell you how.
The general setting is this: You have a bunch of self-made help-classes
organized in some classdirectory somewhere in the filesystem. You use these
in your programming from time to time. You have set a classpath-varible
in your OS such that Java could find your help-classes.
Now you want to create executable jar-files so that you could publish your work.
My problem was that while I added all needed classes in a jar-file, the main-class
couldn't find the others because they were referenced incorrectly. The solution I
came up with may not be elegant, but it works. I copied the main-class and all directories
(only one in my case) just as they appear in the classpath-directory, to the same temporary
directory. Then I created the jar-file from there, using: jar -cmfv Direkt2b.txt Direkt2b.jar Direkt2b.class extra/*.class
I suspected that incorrect referencing was the problem and I tried several variations on the theme above
before giving up and writing the first post. Part the problem was that I didn't get any error messages,
just an annoying error-sound double-clicking the jar-file. I learned later that you could run jar-files from
the command -prompt using: java -jar myjarfile.jar. This way you get a more useful response.
I guess there is a way to include the classpath instead somehow, but I will use my method for now.
I hope this was helpful to somebody.