@Override protected void layoutPlotChildren() {
        super.layoutPlotChildren();

        double height = getLayoutBounds().getHeight();
        getData().forEach(series -> {
            final Path[] paths = getPaths(series);
            if (null == paths) { return; }
            if (isSmoothed()) { smooth(paths[1].getElements(), paths[0].getElements(), height); }
            paths[0].setVisible(ChartType.AREA == getChartType());
            paths[0].setManaged(ChartType.AREA == getChartType());
        });
    }
This method won't work in Java 9 any longer because it makes use of com.sun packages !!!
src/main/java/eu/hansolo/tilesfx/chart/SmoothedChart.java