Packing Java class files into a JAR

DublinDilbert · 12-03-2007 4:19pm #1

Hi all,

I'm trying to pack a number of Java files into a Jar file, which i can execute by just clicking on it...

I can build a Jar file, but i have to execute it from the command prompt using:-
java -jar example.jar

If i just click on the Jar file in explorer, i just get a "main class not found error"

I've tried all the different options, including using a manafest file (also the trick about leaving a blank line at the end of it ) ect...

Anyone any ideas??

OfflerCrocGod · 12-03-2007 6:06pm

inside a META-INF folder I have a file called MANIFEST.MF with

Manifest-Version: 1.0
Created-By: 1.5.0_03 (Sun Microsystems Inc.)
Main-Class: SongSync

inside it and no empty line at the top. Works for me, might be something in your command line options for jar.

Hobbes · 12-03-2007 6:13pm

Offler pretty much has the jist of it.

Google is your friend.

http://csdl.ics.hawaii.edu/~johnson/613f99/modules/04/jar-files.html

OfflerCrocGod · 12-03-2007 6:15pm

This website here explains it all.

OfflerCrocGod · 12-03-2007 6:16pm

Hobbes spying on my browsing

btw DublinDilbert I just jarred an unrelated project by following exactly those instructions and it worked just fine.

DublinDilbert · 13-03-2007 9:44am

Hi Guys,

thanks for the replies....

I inflated the Jar file and i have the manafest file in the correct location, and it looks ok:-
Manifest-Version: 1.0
Created-By: 1.6.0 (Sun Microsystems Inc.)
Main-Class: BookServer

I can run the Jar from the comand line no problem... but when i double click on the Jar file it says it can't find "main".

Basically I'm trying to pack the Jar file so someone just needs to click on it to run it...

thanks again,
DD

DublinDilbert · 13-03-2007 10:25am

Hi All,

Had another quick look, it looks like an older version of the JVM is being called when I try open the JAR file by double clicking on it..

I have version 1.6 installed, and when i run from the command prompt this is what runs... but when i double click on it 1.5 is running...

I wonder is that it... .

Dave

Hobbes · 13-03-2007 11:21am

What version is required to run? You may have to specify that in the manifest as well.

DublinDilbert · 13-03-2007 11:36am

Well at the comand prompt I've set my path so i get Java 1.6.... but when i double click on the JAR file it wants to launch with 1.5 which i had installed before, I'd say just windows has associated the JAR files with the earlier JVM... It's the only think i can think of, as to why it can run the JAR file from the command prompt and not from windows...

If anyone knows of any applications that can make the JAR file look like an EXE that would be great also.. I've tried one and i get the same error as when i click on the JAR file "can't find main"....

thanks again...

Packing Java class files into a JAR

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