Не строится график LineChart - Java

public class Main extends Application {
 
    private double X=-2;
    @FXML  LineChart<Number,Number> lineChart;
    @Override
    public void start(Stage primaryStage) throws Exception{
 
        Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
        primaryStage.setScene(new Scene(root, 460, 325));
        XYChart.Series<Number,Number> series = new XYChart.Series();
        while(X<3){
            series.getData().add(new XYChart.Data<>(X,MathV.f(X)));
            System.out.println(X +": "+MathV.f(X));
            X+=0.5;
        }
        lineChart.
       getData().       // NullPointerException
        add(series);
        primaryStage.show();
    }

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

<?xml version="1.0" encoding="UTF-8"?>
 
<?import javafx.scene.chart.LineChart?>
<?import javafx.scene.chart.NumberAxis?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>
 
<AnchorPane id="AnchorPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="325.0" prefWidth="460.0" xmlns="http://javafx.com/javafx/8.0.102" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
    <children>
        <Button fx:id="button" layoutX="85.0" layoutY="12.0" mnemonicParsing="false" onAction="#onClickMethod" prefHeight="52.0" prefWidth="93.0" text="Click Me!" />
      <TextField fx:id="text" layoutX="19.0" layoutY="63.0" prefHeight="25.0" prefWidth="159.0" text="Введите точность" />
      <TextField fx:id="textx1" layoutX="19.0" layoutY="13.0" prefHeight="25.0" prefWidth="66.0" text="x1 = " />
      <TextField fx:id="textx2" layoutX="19.0" layoutY="38.0" prefHeight="25.0" prefWidth="66.0" text="x2 =" />
      <LineChart fx:id="Chart" layoutX="5.0" layoutY="91.0" prefHeight="230.0" prefWidth="448.0" title="График функции">
        <xAxis>
          <NumberAxis side="BOTTOM" />
        </xAxis>
        <yAxis>
          <NumberAxis side="LEFT" />
        </yAxis>
      </LineChart>
    </children>
</AnchorPane>