title: Check if JTable contains column with identifier
body: <p>Simple question. Is there any way to check if a <code>JTable</code> contains a column before calling <code>getColumn(Object identifier)</code> ?</p>
  
  <pre><code>JTable table = ...;
  table.getColumn("header");
  </code></pre>
  
  <p><code>getColumn()</code> throws a <code>IllegalArgumentException</code> if the header doesn't exist. So, is catching that exception the only way to check for the column? Looking for a <code>hasColumn()</code> or <code>doesColumnExist()</code> or <code>isColumnValid()</code> but, alas, nothing.</p>