Using country as the category

The elements of the bar chart are set up in the simpleBarChartByCountry method. The title of the chart is set and a BarChart class instance is created using the two axes. The chart, its X axis, and its Y axis also have labels that are initialized here:

public void simpleBarChartByCountry(Stage stage) { 
    stage.setTitle("Bar Chart"); 
    final BarChart<String, Number> barChart 
                = new BarChart<>(xAxis, yAxis); 
    barChart.setTitle("Country Summary"); 
    xAxis.setLabel("Country"); 
    yAxis.setLabel("Population"); 
    ... 
} 

Next, the first three series are initialized with a name, and then the country and population data for that series. A helper method, addDataItem, as introduced in the previous section, is used to add the data to each series:

series1.setName("1950"); 
addDataItem(series1,belgium, 8639369); 
addDataItem(series1,france, 42518000); 
addDataItem(series1,germany, 68374572); 
addDataItem(series1,netherlands, 10113527); 
addDataItem(series1,sweden, 7014005); 
addDataItem(series1,unitedKingdom, 50127000); 

series2.setName("1960"); 
addDataItem(series2,belgium, 9118700); 
addDataItem(series2,france, 46584000); 
addDataItem(series2,germany, 72480869); 
addDataItem(series2,netherlands, 11486000); 
addDataItem(series2,sweden, 7480395); 
addDataItem(series2,unitedKingdom, 52372000); 

series3.setName("1970"); 
addDataItem(series3,belgium, 9637800); 
addDataItem(series3,france, 51918000); 
addDataItem(series3,germany, 77783164); 
addDataItem(series3,netherlands, 13032335); 
addDataItem(series3,sweden, 8042803); 
addDataItem(series3,unitedKingdom, 55632000); 

The last part of the method creates a scene instance. The three series are added to the scene and the scene is attached to the stage using the setScene method. A stage is a class that essentially represents the client area of a window:

Scene scene = new Scene(barChart, 800, 600); 
barChart.getData().addAll(series1, series2, series3); 
stage.setScene(scene); 
stage.show(); 

The last of the two methods is the start method, which is called automatically when the window is displayed. It is passed the Stage instance. Here, we call the simpleBarChartByCountry method:

public void start(Stage stage) { 
    simpleBarChartByCountry(stage); 
} 

The main method consists of a call to the Application class's launch method:

public static void main(String[] args) { 
    launch(args); 
} 

When the application is executed, the following graph is displayed: