title: Packaging a class directory into a Jar file
body: <p>I have a directory containing a sub-directory named <code>classes</code>. The <code>classes</code> sub-directory contains other directories and compiled <code>.class</code> files. I would like to assemble a Jar file from the content of the <code>classes</code> sub-directory.</p>
  
  <p>How do I package a directory into a Jar file?</p>