Exporting to an Excutable Jar

[KeyLay]

I am not quite new to Java, but I am having a problem with exporting to a jar file. It is really frustrating because I have other files that have been exported the same way that work fine. But here is my problem. I can run my problem fine in Eclipse. It works great. Now, I want to share it with the world (or a few friends), however I am having problems doing this.

It gives me the error: "Could not find the main class: GameLogic.Chess. Program will now exit"

This is what I have tried. Looking at the MAINFEST.MF file inside the jar. It looks like this:

Manifest-Version: 1.0
Class-Path: .
Main-Class: GameLogic.Chess

So that looks right. I have reinstalled Eclipse and Java. I have taken the Jar and put it on another computer and it ran fine, but when I took it to another machine that was imaged from the other one it got the same error I am receiving. (weird)

I have tried the plug-in fatjar and I get the same result.

I have taken the program apart and commented everything out but the JFrame. Still doesn't work. I don't know what to try next. So I figured I would try to ask a community if they knew about anything else I could try.

Thanks,

KeyLay

[Junky]

Clearly your classpath is incorrect.

[KeyLay]

Ok. How can I correct this?

[doWhile]

Cross posted at Exporting to an Excutable Jar

[Norm]

I have taken the Jar and put it on another computer and it ran fine

That is very strange. How can the same jar file work on one computer and not on another???

What is different between the machines where it works and where it does not work?

[KeyLay]

The strange thing is I created it on my notebook. Windows 7 64 bit. No good. Then I have an XP computer and it works fine (same file). Took it to an imaged computer to the XP machine and no joy. Take it to my mac, and it works. It is getting frustrating.

[Norm]

Are the error messages the same on the PCs where it does not work?
What versions of java are involved?

[KeyLay]

Every machine with the exception of the mac is running the latest JDK 1.7. The only error message I receive is "Could not find the main class: GameLogic.Chess. Program will now exit" Which is the correct name of where my main class is located.

[KeyLay]

Also, I can get all my computers to run it from eclipse.

[Norm]

No ideas. If the same jar file works here and not there and where it does not work it reads the manifest file from th e jar file, I can not think of how that can be.
What is the Class-Path: . entry for? Are there other files the program reads from the current directory?

On a PC where it does not work could you open a command prompt, change to the folder with the jar file and enter the command: java -jar <YOURJARFILENAME>.jar
Copy the contents of the command prompt window:
Click on Icon in upper left corner
Select Edit
Select 'Select All' - The selection will show
Click in upper left again
Select Edit and click 'Copy'

Paste here.

Be sure to come back and let us know when you get it to work.

[KeyLay]

That was helpful. I got this so far. This gives me a whole new range of things to try now.

Exception in thread "main" java.lang.NoClassDefFoundError: chess/jar
Caused by: java.lang.ClassNotFoundException: chess.jar
at java.net.URLClassLoader$1.run(URLClassLoader.java: 202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.j ava:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:3 06)
at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:2 47)

[KeyLay]

I can't follow directions. That was for java chess.jar. This is for java -jar chess.jar

java -jar chess.jar
Exception in thread "main" java.lang.UnsupportedClassVersionError: GameLogic/Chess : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader. java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java :615)
at java.security.SecureClassLoader.defineClass(Secure ClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader .java:283)
at java.net.URLClassLoader.access$000(URLClassLoader. java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java: 197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.j ava:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:3 06)
at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:2 47)

[Norm]

Unsupported major.minor version 51.0

The java source files were compiled by java 1.7 and you are trying to execute them with an older version.
In a command prompt enter: java -version
to see what version of the java command you are using.

[KeyLay]

Thank you so much Norm. You really helped me out. I changed the library's in eclipse to use both JDK 1.7 and 1.6 and that seems to work great.

[Norm]

Its interesting that the external error message is a bit misleading.

[KeyLay]

Thank you so much. My friends and I can now play weird chess variants we thought would be fun to create. Now to see if this problem was worth the time and effort I put into it.

[Norm]

Have fun.