JFreeChart chart1 = new JFreeChart("Title", 
                new Font("SansSerif", Font.PLAIN, 12), new PiePlot(), true);
        JFreeChart chart2 = new JFreeChart("Title", 
                new Font("SansSerif", Font.PLAIN, 12), new PiePlot(), false);
        assertFalse(chart1.equals(chart2));
        assertFalse(chart2.equals(chart1));