title: Set default value in JAXB
body: <p>I have an xml file as following and when the filePath2 is null or empty I want the value of that to be of filePath1's value. Is there a way in which I can achieve this through JAXB.</p>
  
  <pre><code>&lt;file filePath1="C:/filePath"&gt;
     &lt;subFile name="Test"&gt;
        &lt;filePath2&gt;&lt;/filePath2&gt;   
     &lt;/subFile&gt;
  &lt;file/&gt;
  </code></pre>
  
  <p>I don't want to hardcode the default value. If the value for filePath2 is null or blank("") I want to set the filePath1 attribute as the value of 'String filePath'. Is there a way to do it via a setter in JAXB?</p>