Set label of CategoryAxis into barChart javafx - javafx

Question

I have created a barChart in javaFX and I have a problem with categoryAxis. Practice I would like to divide the number of CategoryAxis by 1000. For the moment the graph I get is this:
When I divide the values by 1000 then the graph changes the y axis.
How should I do to get the xaxis values as the second graph with barChart of the first pictures?
Class to populate and show the graph.
package application;
import java.io.File;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.util.ArrayList;
import javafx.scene.Scene;
import javafx.scene.chart.Axis;
import javafx.scene.chart.BarChart;
import javafx.scene.chart.CategoryAxis;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.ScatterChart;
import javafx.scene.chart.XYChart;
import javafx.scene.chart.XYChart.Series;
import javafx.stage.Stage;
import spectrogram.SpectrogramExtractor;
public class ControllerSpectrogram {
private final static double MINSPECTROGRAMHZ = 20.0;
static DecimalFormat df = new DecimalFormat("#.##");
#SuppressWarnings("unchecked")
public static void plotSpectrogramFull(File file, Stage stage) {
df.setRoundingMode(RoundingMode.CEILING);
final CategoryAxis xAxisSpectrogram = new CategoryAxis();
final NumberAxis yAxisSpectrogram = new NumberAxis();
final BarChart<String,Number> scatterChartSpectrogram =
new BarChart<String,Number>(xAxisSpectrogram,yAxisSpectrogram);
ArrayList<Double> extractedData;
ArrayList<Double> extractedTime;
scatterChartSpectrogram.getData().clear();
scatterChartSpectrogram.setOpacity(0.8);
scatterChartSpectrogram.setAnimated(true);
xAxisSpectrogram.setLabel("Time(s)");
yAxisSpectrogram.setLabel("Spectrogram(Hz)");
try {
extractedData = SpectrogramExtractor.extractionSpectrum();
extractedTime = SpectrogramExtractor.pointTime();
Series<String, Number> series = new XYChart.Series<String, Number>();
for (int i = 0; i < extractedData.size(); i=i+2) {
if (extractedData.get(i)> MINSPECTROGRAMHZ) {
extractedTime.set(i, extractedTime.get(i)/1000);
series.getData().add(new XYChart.Data<String, Number>(df.format(extractedTime.get(i)), extractedData.get(i)));
}
}
Scene scene = new Scene(scatterChartSpectrogram, 1000, 600);
scatterChartSpectrogram.getData().add(series);
stage.setScene(scene);
stage.show();
extractedData.clear();
} catch (java.lang.Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
This is the method (in other class)
public class SpectrogramExtractor {
static ArrayList<Double> pointTime = new ArrayList<>();
public static ArrayList<Double> pointTime(){
Double countTime = 0;
for(int i=0; i<100; i++){
countTime = countTime + 0.0196356952;
pointTime.add(countTime);
return pointTime;
}
public static ArrayList<Double>extractionSpectrum(){
//and you can try to populate extractedData whit 100 elements (what you want)
}
}