Could not find Main class problem

[sonname]

I've seen questions regarding this problem posted in many places, but no solution that works for me. I have the problem simplified so maybe we can get a solution:

The error ("could not find the main class") ocurrs only on machines with just
a jre (no jdk installed) from the following command when using Start->Run:
javaw -jar c:/trunk/dev/java/test/jartest.jar

BUT,
The error does not occur when using java instead of javaw.

ALSO,
BOTH ways of running work fine on a machine with the jdk installed.

I have the following simple code:
//----------
import javax.swing.JOptionPane;
public class jartest
{
public jartest()
{
JOptionPane.showMessageDialog(null, "hey", "jartest", JOptionPane.INFORMATION_MESSAGE);
}

public static void main( String args[] )
{
jartest jt = new jartest();
}
}
//---------- end of file

--------------------
my environment is WindowsXP Pro

$ java -version
java version "1.5.0_02"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_02-b09)
Java HotSpot(TM) Client VM (build 1.5.0_02-b09, mixed mode)

javac -version
javac 1.5.0_02
javac: no source files
....

--------------------
I build my jar file as follows:
javac -d . jartest.java
jar cfm jartest.jar mainFile *.class
--------------------
My mainFile is simple:
Main-Class: jartest
--------------------
the client environment is WindowsXp Pro
$ java -version
java version "1.5.0_02"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_02-b09)
Java HotSpot(TM) Client VM (build 1.5.0_02-b09, mixed mode, sharing)
--------------------

Why does this happen and what is the solution?

 

[byam]

I think I see this error before. If I remember correctly, it's due to the jartest class is not under any package. Try put the jartest class in a package say "myPakage". then in the manifest file:

Main-Class: myPackage.jartest