Creating Charts in JavaFX - JavaFX 8: A Definitive Guide to Building Desktop, Mobile, and Embedded Java Clients - page 365

StackPane root = new StackPane();
root.getChildren().add(barChart);
primaryStage.setScene(new Scene(root, 400, 250));
primaryStage.show();
}
Once we replace the import for javafx.scene.chart.ScatterChart with one for javafx.scene.chart.
BarChart , we can build the application and run it. The result is a BarChart similar to that shown in Figure 8-11 .
Figure 8-11. Using BarChart for highlighting differences between the values
Although the result indeed shows the differences between the values for each year, it is not very clear because the
bars are rather small. With a total scene width at 400 pixels, there is not much space to render large bars. However,
the BarChart API contains methods to define the inner gap between bars and the gap between categories. In our case,
we want a smaller gap between the bars, for example, one pixel. This is done by calling
barChart.setBarGap(1);
Adding this single line of code to the start method and rerunning the application results in the output shown
in Figure 8-12 .