title: Jasper Reports crosstab sorting with comparatorExpression
body: <p>I'm trying to sort my dynamic columns in a cross tab according to some custom scheme.  </p>
  
  <p>In the docs I found mention of <i>comparatorExpression: Crosstab group bucket comparator expression. The result of this expression is
  used to sort the buckets, in ascending or descending order. If no comparator
  expression is specified, the natural order will be used.</i></p>
  
  <p>but I don't understand what the expression should look like.  Can I somehow use a regular java comparator?  Can someone share an example?</p>