title: What is the purpose of List<Void>?
body: <p>I didn't even know this was doable, but I saw while perusing some code online a method with a signature like this:</p>
  
  <pre><code>public List&lt;Void&gt; read( ... )
  </code></pre>
  
  <p>... What?  Is there ever a reason to do this?  What could this <code>List</code> even hold?  As far as I was aware, it's not possible to instantiate a <code>Void</code> object.</p>