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JAR execution problems

Bryan Lemmer

Joined: Feb 01, 2007
Posts: 11
Hi all,

I am having a problem executing my main java class from a executable jar.

I use the standard "hello world" app to test the program. i complile the program and run it through the command prompt and it all worked fine.

I then use the following statement "jar cvfm test.jar manifest.txt *.class"
which creates the jar file but when i double click on the file nothing happens???

am i doing something wrong or is there a setting somewhere that i need to set.


Joanne Neal

Joined: Aug 05, 2005
Posts: 3742
Is there a Main-Class header in your manifest file ?

Bryan Lemmer

Joined: Feb 01, 2007
Posts: 11
here is the code for the class and the mainifest entry:

public class mainTest
public static void main(String args[])
System.out.println("this is the correct way to run a java app");


Main-Class: mainTest
Jesper de Jong
Java Cowboy
Saloon Keeper

Joined: Aug 16, 2005
Posts: 14991

What happens if you type this on the command line to run the application:

java -jar test.jar

Do you get any error messages or does the program run as you'd expect?

Note: Your test program prints out a line of text to the console window. If you start an executable JAR file by double-clicking it, the console window is not opened, and you won't see the output of your program. So, you don't see anything happen.

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Bryan Lemmer

Joined: Feb 01, 2007
Posts: 11
Thanks Jesper,

I am an IDIOT!! when executing it from the comand prompt it prints the line. Another question while we are on the subject... why doesnt it print a line to the command prompt if i have it open and then double click on the jar file?

I agree. Here's the link:
subject: JAR execution problems
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