title: Why eclipse doesn't see implemented interfaces?
body: <p>I've imported jfreechart-fse from here: <a href="https://github.com/jfree/jfreechart-fse">https://github.com/jfree/jfreechart-fse</a>
  and I've imported this to eclipse as maven project.</p>
  
  <p>After that, I have many problems, for example in class ChartPanel in org.jfree.chart paskage, eclipse doesn't see "implements" section, and notice</p>
  
  <pre><code>@Override
      public void actionPerformed(ActionEvent event) {...}
  </code></pre>
  
  <p>as a problem. The same situation is in many other cases.</p>
  
  <p>Can you tell what is wrong with that?</p>