title: Impossible to undeploy CustomCode jar (and therefore impossible to deploy a newer version)
body: <p>I am giving a try with the <a href="http://api.shephertz.com/app42-dev.php" rel="nofollow noreferrer">app42 PaaS solution from Shephertz</a>, and especially its <a href="http://api.shephertz.com/tutorial/Server-Side-Custom-Code/?index=customcode,wrd" rel="nofollow noreferrer">CustomCode feature</a> to deploy Java server-side code.</p>
  
  <p>I managed to correctly deploy one version of my server-side "CustomCode" jar (using "ant deploy" command, like in <a href="https://github.com/shephertz/App42_CustomCode_Sample/" rel="nofollow noreferrer">the provided sample</a>).</p>
  
  <p>The problem is that I can't undeploy it</p>
  
  <ul>
  <li>either from the "ant undeploy" command, cf. this error</li>
  </ul>
  
  <p><img src="https://i.stack.imgur.com/ylS0d.png" alt="enter image description here">
  (the html returned looking like this)
  <img src="https://i.stack.imgur.com/eYLh8.png" alt="enter image description here"></p>
  
  <p><br/><br/>
   - or from the App42 management console (POST is successful but returns failure message)
  <img src="https://i.stack.imgur.com/IBRvz.png" alt="enter image description here"></p>
  
  <p><br/><br/>
  Obviously, this prevents me to deploy a new version of this jar, cf. this error
  <img src="https://i.stack.imgur.com/dQe7L.png" alt="enter image description here"></p>