title: IntelliJ IDEA: Is there a way to list all interfaces implemented by a class and its parents?
body: <p>I work on a relatively complex Java project where classes commonly have four or five ancestors before <code>Object</code>. Given such a class, e.g. <code>D</code> in a hierarchy like this: <code>Object &gt; A &gt; B &gt; C &gt; D</code>, I would like to know what all interfaces it effectively implements. That is, I am also interested in seeing that <code>D</code> implements, say, <code>Serializable</code> even if that is declared only in the declaration of class <code>B</code> and even when <code>D</code> does not actually implement any of the methods specified by the interface (naturally, if talking about <code>Serializable</code>).</p>
  
  <p>Some potential sources of this information I tried include:</p>
  
  <ul>
  <li>using "Group by Defining Type" in the Structure window -- but that won't show empty interfaces (= interfaces without methods), and</li>
  <li>the "Hierarchy" window -- but that does not include interfaces when viewing the hierarchy for a class.</li>
  </ul>
  
  <p>Is there a way to obtain this information in IDEA without having to open files of all ancestor classes of the class in question?</p>