Grafico de linhas JFreeChart [RESOLVIDO]

JFrame jf = new JFrame();
jf.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
jf.setSize( 500, 500 );

DefaultCategoryDataset ds = new DefaultCategoryDataset();
ds.addValue( 0, "a", "x" );
ds.addValue( 2.3, "a", "y" );

ds.addValue( 8, "b", "x" );
ds.addValue( 1.5, "b", "y" );

ds.addValue( 0.5, "c", "x" );
ds.addValue( 7, "c", "y" );

JFreeChart chart = ChartFactory.createLineChart(
        "Teste",
        "Categorias",
        "Valores", ds,
        PlotOrientation.HORIZONTAL, true, true, true );

CategoryItemRenderer renderer = chart.getCategoryPlot().getRenderer();
renderer.setSeriesPaint( 0, new Color( 0, 255, 0 ) );
renderer.setSeriesPaint( 1, Color.YELLOW );
renderer.setSeriesPaint( 2, new Color( 0, 100, 155 ) );

ChartPanel panel = new ChartPanel( chart );
jf.add( panel, BorderLayout.CENTER );

jf.setVisible( true );

Tipo:

Ponto 1 = (3, 4);

Ponto 2 = (2, 2);

Ponto 3 = (4, 1);

Ponto 4 = (3, 2);