plot1.setNeedlePaint(new GradientPaint(9.0f, 8.0f, Color.red, 
                7.0f, 6.0f, Color.blue));
        assertFalse(plot1.equals(plot2));
        plot2.setNeedlePaint(new GradientPaint(9.0f, 8.0f, Color.red, 
                7.0f, 6.0f, Color.blue));
        assertTrue(plot1.equals(plot2));