Failed to load Main-Class manifest attribute from Hello.jar???

Question

HI all
This is my first post, I hope its in the right section
I followed the tutorial on [http://www.cs.princeton.edu/introcs/85application/jar/jar.html|http://www.cs.princeton.edu/introcs/85application/jar/jar.html] and I tried out the simple example below
A simple example. Let's say we wanted to distribute the simple program Hello.java as a JAR. First, we create a text file named Hello.mf which contains:Manifest-Version: 1.0
Main-Class: Hello
Then, we create the archive by typing:
jar cmf Hello.mf Hello.jar Hello.class Hello.java
and run it by typing:
java -jar Hello.jar 
But when I ran the command java -jar Hello.jar the following error message showed on my command prompt
Failed to load Main-Class manifest attribute from Hello.jar
I don't know what I have done wrong, i followed the tutorial to the letter.
Can anyone shed some light on whats going wrong please?
Many thanks
HLA91

Answer 1

Sorry about double post but i dont know whether editing my first one will bump the thread, and i need it bumped :).
I downloaded netbeans and I built my project and a jar file was created in oblong/dist (oblong is my project name) but again when i try to run the file the warning
Failed to load Main-Class manifest attribute from oblong.jar
appears and I dont know what i can do this time seen as i dont make the manifest file (read prior posts to see what i previously did wrong) , the compiler does it all for me so either im missing something that i have to do before building my project or netbeans is messing up for some strange reason. Can anyone provide insight?
Many thanks
HLA91