title: Table like java data structure
body: <p>I need to implement some kind table-like data structure that stores info like this in Java:</p>
  
  <pre><code>+--------+-------+-----+
  |  sij   |   i   |  j  |
  +--------+-------+-----+
  |   45   |   5   |  7  |
  +--------+-------+-----+ 
  |   33   |   1   |  6  |
  +--------+-------+-----+ 
  |   31   |   0   |  9  |
  +--------+-------+-----+ 
  |   12   |   8   |  2  |
  +--------+-------+-----+ 
  </code></pre>
  
  <p>and I have to be able to sort the table by the <code>sij</code> parameter. I've made some tests with <code>ArrayList</code> and <code>HashMap</code>, but I can't make them work well.</p>