title: Unable to load the mojo 'add-source' (or one of its required components) from the plugin 'org.codehaus.mojo:build-helper-maven-plugin:1.9'
body: <p>I am using the following Maven plugin:</p>
  
  <pre><code>        &lt;plugin&gt;
              &lt;groupId&gt;org.codehaus.mojo&lt;/groupId&gt;
              &lt;artifactId&gt;build-helper-maven-plugin&lt;/artifactId&gt;
              &lt;version&gt;1.9&lt;/version&gt;
              &lt;executions&gt;
                  &lt;execution&gt;
                      &lt;id&gt;add-source&lt;/id&gt;
                      &lt;phase&gt;generate-sources&lt;/phase&gt;
                      &lt;goals&gt;
                          &lt;goal&gt;add-source&lt;/goal&gt;
                      &lt;/goals&gt;
                      &lt;configuration&gt;
                          &lt;sources&gt;
                              &lt;source&gt;${basedir}/target/generated/src/main/java&lt;/source&gt;
                          &lt;/sources&gt;
                      &lt;/configuration&gt;
                  &lt;/execution&gt;
              &lt;/executions&gt;
          &lt;/plugin&gt;
  </code></pre>
  
  <p>Eclipse keeps showing me the following error:</p>
  
  <blockquote>
    <p>Execution add-source of goal org.codehaus.mojo:build-helper-maven-plugin:1.9:add-source failed: Unable to load the mojo 'add-source' (or one of its required components) from the plugin 'org.codehaus.mojo:build-helper-maven-plugin:1.9' (org.codehaus.mojo:build-helper-maven-plugin:1.9:add-source:add-source:generate-sources)
    org.apache.maven.plugin.PluginExecutionException: Execution add-source of goal org.codehaus.mojo:build-helper-maven-plugin:1.9:add-source failed: Unable to load the mojo 'add-source' (or one of its required components) from the plugin 'org.codehaus.mojo:build-helper-maven-plugin:1.9'</p>
  </blockquote>
  
  <p>What am I doing wrong?</p>