Q:

How to make plot a curve using JFreeChart? 

I have managed to plot a linear graph.  The following is the code:
private JPanel createGraph() {

        JPanel panel = new JPanel();
        XYSeries series = new XYSeries("MyGraph");
        series.add(0, 1);
        series.add(1, 2);
        series.add(2, 5);
        series.add(7, 8);
        series.add(9, 10);

        XYSeriesCollection dataset = new XYSeriesCollection();
        dataset.addSeries(series);

        JFreeChart chart = ChartFactory.createXYLineChart(
                "XY Chart",
                "x-axis",
                "y-axis",
                dataset, 
                PlotOrientation. VERTICAL,
                true,
                true,
                false
                );
        ChartPanel chartPanel = new ChartPanel(chart);

        panel.add(chartPanel);

        return panel;
    }

However, it is not a smooth curve, but straight lines.  How can I make it smooth please? 

A:

I believe that you are looking for XYSplineRenderer
You should be able to do
chart.getXYPlot().setRenderer(new XYSplineRenderer());

after your chart is constructed.