problem in running jar file

[sagar khana]

howdy
hey i am having problem in running jar file when i double click it says error as shows in fig i have added main class but still its keep coming please show me some guidance

thank you very much for your help
god bless you

[Greg Brannon]

I'm not able to see your figure. Please copy and paste the error message you're receiving exactly as it appears.

[sagar khana]

Greg Brannon wrote:I'm not able to see your figure. Please copy and paste the error message you're receiving exactly as it appears.

ok sorry

here what it is written:

"A java exception has occured."

[Rob Spoor]

Run the JAR file from the command line using java -jar, that way you'll get to see the actual exception / error.

[Darryl Burke]

Is the program in the .jar something you coded or someone elses's code?

[sagar khana]

thank you so much for your reply

Rob Spoor wrote:Run the JAR file from the command line using java -jar, that way you'll get to see the actual exception / error.

ya i tried it says following error:

Exception in thread main java.lang.NullPointerException
at sun.launcher.LauncherHelper.getMainClassFromJar<Unkown Source>
at sun.launcher.LauncherHelper.checkAndLoadMain<Unkown Source>

i have added main class in txt file before making jar file and there were no error in program


when i make jar file using JOptionPane it runs ok but when i use my code it gives error

thank you

[sagar khana]

thank you for your reply

Darryl Burke wrote:Is the program in the .jar something you coded or someone elses's code?

it is my code and its running perfect in .java file

[Rob Spoor]

Please show us the contents of your MANIFEST.MF file.

[sagar khana]

Thanks for your reply

Rob Spoor wrote:Please show us the contents of your MANIFEST.MF file.

this is the content in Mainfest.mf
Manifest-Version: 1.0
Created-By: 1.7.0_01 (Oracle Corporation)

thank you very much

[Rob Spoor]

Where is the Main-Class entry? Without that, a JAR file is not an executable JAR file.