title: Maven javadoc plugin 3.1.0 not generating aggregate javadocs
body: <p>I have a multi-module project for which I'd like to generate aggregate javadoc reports. I am using <code>maven-javadoc-plugin</code> version 3.1.0. Here's the reporting section of pom.xml file:</p>
  
  <pre><code>&lt;reporting&gt;
   &lt;plugins&gt;
    &lt;plugin&gt;
      &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
      &lt;artifactId&gt;maven-javadoc-plugin&lt;/artifactId&gt;
      &lt;version&gt;3.1.0&lt;/version&gt;
      &lt;reportSets&gt;
        &lt;reportSet&gt;
          &lt;id&gt;non-aggregate&lt;/id&gt;
          &lt;reports&gt;
            &lt;report&gt;javadoc&lt;/report&gt;
          &lt;/reports&gt;
        &lt;/reportSet&gt;
        &lt;reportSet&gt;
          &lt;id&gt;aggregate&lt;/id&gt;
          &lt;inherited&gt;false&lt;/inherited&gt;
          &lt;reports&gt;
            &lt;report&gt;aggregate&lt;/report&gt;
          &lt;/reports&gt;
        &lt;/reportSet&gt;
      &lt;/reportSets&gt;
    &lt;/plugin&gt;
   &lt;/plugins&gt;
  &lt;/reporting&gt;
  </code></pre>
  
  <p>I am using <code>mvn site:site site:stage</code> goals to generate the javadoc reports. When I run this command, I expect to see <code>apidocs</code> directory containing <code>index.html</code> under <code>target/site/</code> but I don't see <code>apidocs</code> directory.</p>
  
  <p>What's interesting is if I switch to <code>3.0.1</code> version of <code>maven-javadoc-plugin</code>, aggregate javadocs are successfully generated.</p>
  
  <p>I understand that there was a change to how <code>aggregate</code> reports are generated in 3.1.0 as <a href="https://maven.apache.org/plugins/maven-javadoc-plugin/examples/aggregate.html" rel="nofollow noreferrer">documented here</a> and I have used the same reporting setup.</p>
  
  <p>Also, javadocs for individual modules are generated correctly for both versions of the plugin.</p>
  
  <p>Other details:</p>
  
  <ul>
  <li>JDK 8</li>
  <li><code>maven-site-plugin</code> version 3.7.1</li>
  </ul>