title: What is a Virtual file system or a file system in userspace?
body: <p>I just came across a VFS and a filesystem in userspace like <a href="http://fuse.sourceforge.net/" rel="noreferrer">FUSE</a>.</p>
  
  <p>Now, as far as I understand, it simulates a file system, so that an application can have a standard file system hierarchy. But I don't understand, why do we need a separate file system for that? Can't we just create a regular folder structure and place files which will be used by the app?</p>
  
  <p>So, my questions are:</p>
  
  <ol>
  <li><p>What is a VFS? </p></li>
  <li><p>Can you give some real world examples, use cases where VFS is used.</p></li>
  <li><p>What is the benefit of using a VFS?</p></li>
  </ol>
  
  <p>Any Java based VFS?</p>