Running classes in jar

Question

This is probably a fairly stupid question, but I wasn't able to find any documentation for this particular problem.
I created your basic HelloWorld project with the following directory structure:
HelloWorld
|- classes/hello/world/HelloWorld.class
|- src/java/hello/world/HelloWorld.java
|- Manifest.txt
Manifest.txt only has the following line:
Main-Class: hello.world.HelloWorld
Now, I try to jar this up and run it as a jar by performing the following in the HelloWorld directory:
jar cfm hello.jar Manifest.txt classes/wgen/world/HelloWorld.class
java -jar hello.jar
And I get a NoClassDefFoundError: hello/world/HelloWorld exception. What do I have to do so I can run HelloWorld from the jar?
Thanks in advance!

Answer 1

Did you mean classes/wgen/world/HelloWorld.class or classes/hello/world/HelloWorld.class? You used both in your post.
What is the package statement, if any, in the HelloWorld.java source code? How did you test the HelloWorld app before you jar'ed it? What is the output of "jar tf hello.jar"
Assuming the directory path is classes/hello/world/HelloWorld.class, the source code starts with "package hello.world;" and your existing manifest then something like this cd classes
jar cfm hello.jar Manifest.txt hello/world/HelloWorld.class
java -cp hello.jar hello.world.HelloWorld
java -jar hello.jarI always test a jar using the -cp option first to make sure I jar'ed the classes correctly, then test it with the -jar option. If it does not work with -cp then the classes are not jar'ed correctly. If it works with -cp but does not work with -jar, then the manifest is incorrect.