title: how to add a java class to a folder within a jar file
body: <p>using jar on the windows command prompt, how can I add foo.class to a folder "classes" in foo.jar?</p>
  
  <p>I can add the file to the jar using </p>
  
  <blockquote>
    <p>jar uvf foo.jar foo.class</p>
  </blockquote>
  
  <p>but that doesn't put the class in the "classes" folder in the jar.</p>
  
  <p>I know I can use winzip to unzip the jar, add the file, and zip it up again, but that's slow and hopefully unnecessary. </p>