title: why does Files.probeContentType return null
body: <p>i am using java se7 on mac, the oracle preview.</p>
  
  <p>My problem is that "Files.probeContentType" returns null...is it possible that its due to the early status of se7 for mac?
  My code:</p>
  
  <pre><code>if(directory == null) return;
  String content = null;
  try {
      content = Files.probeContentType(directory.toPath());
  } catch (IOException e) {
      JOptionPane.showMessageDialog(main, e.toString());
      return;
  }
  if(content == null)
  {
      return;
  }
  else if(content.contains("image"))
  {
      main.pctviewer.setImage(directory);
  }
  </code></pre>
  
  <p>the name of the file is: </p>
  
  <p>"/Users/admin/Desktop/temp/q12/formulare/Bildschirmfoto 2012-09-11 um 17.57.59.png"</p>
  
  <p>and in debug mode in eclipse if i hover above File "file path = Unis-path(id:145)" is red</p>