title: Hierarchical table column in Java
body: <p>Is there any Java library that supports hierarchical column?</p>
  
  <p>For example (the first three row are columns) :</p>
  
  <pre><code>------------------------------------------------
  2008                                           |
  ------------------------------------------------
  January               | February               |
  ------------------------------------------------
  Week1 | Week2 | Week3 | Week 1 | Week2 | Week3 |
  ------------------------------------------------
  10    | 20    | 14    | 12     | 15    | 3     |
  ------------------------------------------------
  </code></pre>