How to customize PieChart using JFreechart

Question

I need to create a donut pie chart for a 6 type of data. I can able to create chart using JFreechart library.

I need to customize this donut pie chart. For example I need to have little gap between slices of the chart. In my case my donut pie chart will have 6 slices with 6 different color in circle shape with this slices are connect and form the circle.

As per my requirement instead of connected slices I need to create a circle of slices with little gap (empty space) between each slices. I am struggle to create circle of slices with little gap.

Attached the sample image. Highlighted part with the gap between the slice is what I am looking.

Also instead of flat edge slices, need to create curvy edge slices.

This is the code I am trying which creates circular doughnut pie chart without gap.

setInteriorGap -> This property only increase or decreasing the inner circle space.

private String createCustomPieChart(Map<String, Float> pieData, String pieChart) {
        AtomicInteger count = new AtomicInteger(0);
        Integer size = pieData.size();
        try {
            DefaultPieDataset<String> dataset = new DefaultPieDataset<String>();
            pieData.entrySet().stream().forEach(e -> dataset.setValue(e.getKey(), e.getValue()));        
            JFreeChart chart = ChartFactory.createRingChart("Chart Title", dataset, true, false, false);
            chart.setBorderVisible(false);
            chart.getLegend().setBackgroundPaint(Color.WHITE);
            chart.setBorderVisible(false);
            chart.setBackgroundPaint(Color.WHITE);
            
          //Pie Plot area customization
            RingPlot rp = (RingPlot)chart.getPlot();
            rp.setBackgroundPaint(Color.WHITE);
            rp.setSectionDepth(0.10);
            rp.setLabelGap(0.5);
            rp.setOutlineVisible(false);
          //Dynamically generate new color for each section
            pieData.entrySet().stream().forEach(entry -> {rp.setSectionPaint(entry.getKey(), Color.getHSBColor((float)count.get()/size, 1, 1)); count.getAndIncrement();});
            rp.setSeparatorsVisible(false);
            
            rp.setCircular(true);
            rp.setAutoPopulateSectionOutlineStroke(true);
            rp.setInteriorGap(0.25); //To increase or decrease circular size of the chart
            //rp.setLabelLinkMargin(1.00);
            //rp.setOuterSeparatorExtension(2.0);
            rp.setInnerSeparatorExtension(0.90);
            
            rp.setLegendItemShape(new Rectangle(20,20)); // Customizing List of items on chart legend
            
            rp.setLabelBackgroundPaint(Color.WHITE);
            rp.setLabelOutlinePaint(Color.WHITE);
            rp.setLabelGenerator(new StandardPieSectionLabelGenerator("{0}:{1}"));  // change this to display only key or value
            rp.setSimpleLabelOffset(new RectangleInsets(UnitType.RELATIVE, 0.09, 0.09, 0.09, 0.09)); // Customizing Labels on the plot area
            rp.setSimpleLabels(true); // To avoid lines for labels
          //Display some text  at centre
            rp.setCenterTextMode(CenterTextMode.FIXED); 
            rp.setCenterText("Total Split 500");
          //Write to an image
            BufferedImage bufferedImage = chart.createBufferedImage(500, 500);
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            ImageIO.write(bufferedImage, "png", baos);
            return pieChart.replace("graph.jpg", "data:image/png;base64,"+DatatypeConverter.printBase64Binary(baos.toByteArray()));
        }catch (Exception e) {
            e.printStackTrace();
            log.error("Exception from Pie Image generate: {}", e.getMessage());
          }
        return "";
    }