I made a jar file, but it doesn't run in command line like it used to

Question

I made an executable jar file with manifest and everything and when I ran it in the command prompt a while ago, it worked perfectly, but now, I do the same thing, I also recreated the jar a few times, it keeps giving me this error:

Exception in thread "main" java.lang.NoClassDefFoundError: ComputingAverage (wro
ng name: me/kevinossia/mystuff/ComputingAverage)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(Unknown Source)
        at java.security.SecureClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.defineClass(Unknown Source)
        at java.net.URLClassLoader.access$100(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

I am using the java -jar ComputingAverage.jar command. Why do I get this error?

I hope you checked this - http://stackoverflow.com/questions/6334148/exception-in-thread-main-java-lang-noclassdeffounderror — Vikram, Feb 15 '13 at 20:32
And you might also list the contents of the jar file with `jar tvf ComputingAverage.jar` and compare those with the contents of the MANIFEST.MF file. — Alan Krueger, Feb 15 '13 at 20:32
My manifest file looks like this: Main-Class: ComputingAverage — Kevin Ossia, Feb 15 '13 at 20:37
My jar file only contains one class, and the jar tvf ComputingAverage.jar doesn't work, I tried adding "java" before it, and that also didn't work. — Kevin Ossia, Feb 15 '13 at 20:39
execute `jar -tvf ComputingAverage.jar` and post the output so we can see the content of your jar. If the jar doesn't contain `me/kevinossia/mystuff/ComputingAverage.class`, that's the error. Probably you just packaged your jar in a wrong way. — Luigi R. Viggiano, Feb 15 '13 at 20:50
It just says that "jar" is not recognized as an internal or external command, operable program, or batch file. — Kevin Ossia, Feb 15 '13 at 22:05

score 0 · Answer 1 · answered Feb 15 '13 at 20:32

0

Verify your MANIFEST file. It indicates to JVM how your program will run.

For more information, check this article: http://www.mkyong.com/java/how-to-make-an-executable-jar-file/

answered Feb 15 '13 at 20:32

Diogo Moreira

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I did, and I don't see what could have gone wrong. My jar file only contains one class, and that class contains the main function, so I put that into the manifest. – Kevin Ossia Feb 15 '13 at 20:40
Which package is your class in? – Diogo Moreira Feb 15 '13 at 20:44
it is in me.kevinossia.mystuff – Kevin Ossia Feb 15 '13 at 20:49
So your Manifest should look like this: Main-Class: me.kevinossia.mystuff.ComputingAverage – Diogo Moreira Feb 15 '13 at 20:57
Ah, ok. Thanks. But what I don't understand is why this worked earlier, but not now. – Kevin Ossia Feb 15 '13 at 20:59

score 0 · Answer 2 · answered Feb 15 '13 at 20:39

0

You need to make sure the paths match in the jar file and the package header in the java file.

answered Feb 15 '13 at 20:39

hd1

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So, wherever the java file is, that's where the jar file should be? – Kevin Ossia Feb 15 '13 at 20:45

score 0 · Answer 3 · answered Dec 23 '14 at 10:22

you just try my way. Create jar file using eclipse.

Right click on your project->export->java->runnable jar file-> next-> select ComputingAverage in launch configuration dropdown box->select destination export-> select Extarct required libraries into generated jar->finish.

open cmd :- give the command like this "java -jar jarFileName"

Thats it. It should work.

I made a jar file, but it doesn't run in command line like it used to

3 Answers3