Is there a one-liner or some extremely easy to use tool to create utility jars?

Question

I'd like to show other people how to create jars from their code, so they can share it with others. In the meantime, I'd like to make this as easy as possible for them.

What would be the easiest way of doing that?

Answer 1

The impression I have is that jars are really just a .zip files. So you just need to put your classes and manifests into the right folders and use a utility like zip to zip them up into a final .jar file.