Customizer class to remove space between bars in a StackedBar

Hello, 

I created a StackedBar item and want to eliminate the space between the bars. I wrote the following customerize, but the bars are sill spaced, any idea ?

thanks in advnace.

import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.renderer.category.*;

public class CustomizeBarChart extends JRAbstractChartCustomizer {
@Override
public void customize(JFreeChart chart, JRChart jasperChart) {
CategoryPlot categoryPlot = chart.getCategoryPlot();
StackedBarRenderer renderer = (StackedBarRenderer) categoryPlot.getRenderer();
chart.setTitle("Hello");
renderer.setItemMargin(0.0); }}

update:

Here is the scala version of the same code:

import net.sf.jasperreports.engine.JRAbstractChartCustomizer;