Executing the JAR File - ANT HelloWorld Tutorial

[BernieC]

I'm going thru the HelloWorld tutorial in ANT. I've executed the echo command to create a manifest and created the HelloWorld.jar file using the manifest. When I try to execute the jar file (C:\ANT>java -jar Build\jar\HelloWorld.jar), I get " Cannot find or load main class oata.HelloWorld". If this class is in the jar file that is being executed, why is it not found?

Directory structure is as follows:

C:\Ant
C:\ANT\build
C:\ANT\build\classes
C:\ANT\build\classes\oata
C:\ANT\build\classes\oata\HelloWorld.class
C:\ANT\build\jar
C:\ANT\build\jar\HelloWorld.jar


Thanks

[Tolls]

Yes, but what is in the jar file?
Have you retained the package structure such that there is an 'oata' "folder" in the top level of the jar file, containing your class?

[BernieC]

Yes. The jar file has a META-INF folder which contains MANIFEST.MF. The jar file also contains "build/classes/oata/HelloWorld.class"

[BernieC]

Wait a minute. The "oata" folder is not the top level folder. Is that my problem?

Thanks

[BernieC]

Thanks for the help. The piece of data I was missing was that the "oata" folder needed to be the top level folder in the jar file
I figured this out how to make that happen.

Key points: 1. before executing the jar command one must change the directory to the the path of the class file . in my case "C:>ANT\build\classes".
2. if one wants the new jar file to be in a folder other than the "classes" folder, one must enter the full path. In my case "C:\build\jar\HelloWorld.jar".

One other note . If I used the -C parameter before the class file folder name, a jar file was not created. I had to leave out the "-C" to make it work. I don't know what is going on there.

.

[Tolls]

What is the full command you are using when using the -C option, and where are you located when you do that?

[BernieC]

The following will not produce a jar file:

"C:\ANT\build\classes>jar -cfm C:\ANT\build\jar\HelloWorld.jar myManifest -C oata/"


The following DOES produce a jar file:


"C:\ANT\build\classes>jar -cfm C:\ANT\build\jar\HelloWorld.jar myManifest oata/"

[Tolls]

The -C just tells it to change directory to the given directory (oata in your case).
So in that first command you have only told the jar command to change directory...but you haven't given it anything to jar up.

jar -cfm C:\ANT\build\jar\HelloWorld.jar myManifest -C oata .

That '.' there tells it you want to jar up the contents of the current directory, in this case the contents of 'oata' since that is current as of the '-C'.

[BernieC]

That works. I didn't know you needed the period.



Thanks again!!

[Tolls]

The period tells jar that you want to jar the files in the current directory.