title: Separator between header and data in a JTable
body: <p>I would like to build a simple JTable which has no gridlines apart from a single horizontal separator between the table header and table data. The separator should span the entire width of the table exactly like a JSeparator. I have managed to achieve the desired appearance using JLabels and a JSeparator placed within a GridBagLayout, however the result is somewhat unwieldy and I can't help but feel that more concise solutions exist (perhaps using a MatteBorder?). Any help would be much appreciated!</p>
  
  <p>EDIT: The solution can be achieved using the single line of code:</p>
  
  <pre><code>table.getTableHeader().setBorder(new MatteBorder(0,0,1,0, Color.BLACK));
  </code></pre>