code: private void applyBackgroundColor(JRDesignCellContents contents, DJCrosstabRow crosstabRow,
  			DJCrosstabColumn crosstabColumn, int i,int j) {
  
  		Color color = colors[i][j];
  
  		contents.setBackcolor(color);
  	}
docs: Aplies background coloring upon the matrix described in {@link Dj2JrCrosstabBuilder#createCells}}
  @param contents
  @param crosstabRow
  @param crosstabColumn
  @param i
  @param j