jar file problem

[webster]

ok im having a go at creating a jar file. i am using cmd to do it. In the
folder that all my class and stuff is in i used the command "jar cf Jrum.jar
DrumMachine.class play.gif stop.gif hithat.wav snare.wav base.wav
cymbal.wav". It appears to have been successful, it made a jar file, but
when i click on it i get this message, "Java Virtual Machine Launcher,
Failed to load Main-Class manifest attribute from c:\java progs/Jrum.jar"
What does this mean? Have i don't this right? How can i over come this?
I am using "Sams teach yourself java 2" and "java 2 in easy steps" but they
are not helping.
thanks
matt

[Chris]

well you're main application class is inside the jar file, and it
doesn't know where to locate it. so what you will need to do is set
some "attributes" insdie the manifest file that directs it to the
right place.

Main-Class does that. also you will need to put in a CLASS-PATH
attribute if you are referencing anything outside of the standard jdk
library.

example

Manifest-Version: 1.0
Created-By: 1.4.0_03 (Sun Microsystems Inc.)
Main-Class: yyy.zzz.sss.App
CLASS-PATH: ./activation.jar ./mail.jar

the ./ is from the root of where you are running your jar file. (so
these are in the same directory)

hope this helps,

chris
"webster" <tr********@hotmail.com> wrote in message news:<GE*******************@news-server.bigpond.net.au>...

ok im having a go at creating a jar file. i am using cmd to do it. In the
folder that all my class and stuff is in i used the command "jar cf Jrum.jar
DrumMachine.class play.gif stop.gif hithat.wav snare.wav base.wav
cymbal.wav". It appears to have been successful, it made a jar file, but
when i click on it i get this message, "Java Virtual Machine Launcher,
Failed to load Main-Class manifest attribute from c:\java progs/Jrum.jar"
What does this mean? Have i don't this right? How can i over come this?
I am using "Sams teach yourself java 2" and "java 2 in easy steps" but they
are not helping.
thanks
matt

[Phil]

Here is the command I use (you need to add your other files like *.wav)

jar cvfm NewDraw3.jar META-INF/MANIFEST.MF *.class

The manifest file Chris mentioned goes in a file with
name MANIFEST.MF which is in a directory with name META-INF

The file name on the Main-Class: line tells which file
contains the "main" routine, so for me I have

Main-Class: NewDraw3

Phil...

"Chris" <cb********@liquiddatainc.com> wrote in message news:89**************************@posting.google.c om...

well you're main application class is inside the jar file, and it
doesn't know where to locate it. so what you will need to do is set
some "attributes" insdie the manifest file that directs it to the
right place.

Main-Class does that. also you will need to put in a CLASS-PATH
attribute if you are referencing anything outside of the standard jdk
library.

example

Manifest-Version: 1.0
Created-By: 1.4.0_03 (Sun Microsystems Inc.)
Main-Class: yyy.zzz.sss.App
CLASS-PATH: ./activation.jar ./mail.jar

the ./ is from the root of where you are running your jar file. (so
these are in the same directory)

hope this helps,

chris


"webster" <tr********@hotmail.com> wrote in message news:<GE*******************@news-server.bigpond.net.au>...

ok im having a go at creating a jar file. i am using cmd to do it. In the
folder that all my class and stuff is in i used the command "jar cf Jrum.jar
DrumMachine.class play.gif stop.gif hithat.wav snare.wav base.wav
cymbal.wav". It appears to have been successful, it made a jar file, but
when i click on it i get this message, "Java Virtual Machine Launcher,
Failed to load Main-Class manifest attribute from c:\java progs/Jrum.jar"
What does this mean? Have i don't this right? How can i over come this?
I am using "Sams teach yourself java 2" and "java 2 in easy steps" but they
are not helping.
thanks
matt