JavaFX plotting LinexChart - javafx

Question

I am trying to learn how plot graph using JavaFX and there is my code where I trying to draw the very simple sin series:
public class Controller implements Initializable {
final NumberAxis xAxis = new NumberAxis();
final NumberAxis yAxis = new NumberAxis();
#FXML
private LineChart<Number, Number> ExactChart = new LineChart<Number, Number>(xAxis, yAxis);
private Series sin_series = new Series();
#FXML
private void plotTheChart(ActionEvent event){
int N = 100;
double x0 = -Math.PI;
double X = Math.PI;
double h = (X-x0)/(N);
double[] x = new double[N];
double[] y = new double[N];
x[0] = x0;
for(int i = 1; i < N; i++){
x[i] = x[i-1] + h;
}
for(int i = 0; i < N; i++){
y[i] = Math.sin(x[i]);
}
sin_series.setName("sin");
for(int i = 0; i < N; i++){
sin_series.getData().add(new Data(x[i], y[i]));
}
ExactChart.getData().addAll(sin_series);
}
#Override
public void initialize(URL url, ResourceBundle resourceBundle) {
}
}
But when I execute it I face following problem:
Exception in thread "JavaFX Application Thread" java.lang.ClassCastException: class java.lang.Double cannot be cast to class java.lang.String (java.lang.Double and java.lang.String are in module java.base of loader 'bootstrap')
I do not see any part of the code where I am castin double to string. Can you show me where I am wrong?