Using decade as the category

In the following example, we will demonstrate how to display the same information, but we will organize the X axis categories by year. We will use the simpleBarChartByYear method, as shown next. The axis and titles are set up in the same way as before, but with different values for the title and labels:

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

The following string variables are declared for the three decades:

String year1950 = "1950"; 
String year1960 = "1960"; 
String year1970 = "1970"; 

The data series are created in the same way as before, except the country name is used for the series name and the year is used for the category. In addition, six series are used, one for each country:

series1.setName(belgium); 
addDataItem(series1, year1950, 8639369); 
addDataItem(series1, year1960, 9118700); 
addDataItem(series1, year1970, 9637800); 

series2.setName(france); 
addDataItem(series2, year1950, 42518000); 
addDataItem(series2, year1960, 46584000); 
addDataItem(series2, year1970, 51918000); 

series3.setName(germany); 
addDataItem(series3, year1950, 68374572); 
addDataItem(series3, year1960, 72480869); 
addDataItem(series3, year1970, 77783164); 

series4.setName(netherlands); 
addDataItem(series4, year1950, 10113527); 
addDataItem(series4, year1960, 11486000); 
addDataItem(series4, year1970, 13032335); 

series5.setName(sweden); 
addDataItem(series5, year1950, 7014005); 
addDataItem(series5, year1960, 7480395); 
addDataItem(series5, year1970, 8042803); 

series6.setName(unitedKingdom); 
addDataItem(series6, year1950, 50127000); 
addDataItem(series6, year1960, 52372000); 
addDataItem(series6, year1970, 55632000); 

The scene is created and attached to the stage:

Scene scene = new Scene(barChart, 800, 600); 
barChart.getData().addAll(series1, series2,  
    series3, series4, series5, series6); 
stage.setScene(scene); 
stage.show(); 

The main method is unchanged, but the start method calls the simpleBarChartByYear method instead:

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

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