title: Understanding Class<?>
body: <p>I came across this code:</p>
  
  <pre><code>public class RestfulAdage extends Application {
    @Override
    public Set&lt;Class&lt;?&gt;&gt; getClasses() {
      Set&lt;Class&lt;?&gt;&gt; set = new HashSet&lt;Class&lt;?&gt;&gt;();
      set.add(Adages.class);
      return set;
    }
  }
  </code></pre>
  
  <p>I do not understand what <code>Class&lt;?&gt;</code> means.</p>