title: Should I subclass JFrame/JPanel or not?
body: <p>I was used to subclassing the window-classes in other programming environment, but in the java tutorials I usually see something like</p>
  
  <pre><code>JPanel p = new JPanel();
  p.setLayout(new BoxLayout(p, BoxLayout.PAGE_AXIS));
  
  p.add(aComponent);
  p.add(anotherComponent);
  </code></pre>
  
  <p>So what are the conventions in Java regarding subclassing top-container classes?</p>