Из-за чего возникают данные ошибки при вызове графика в новом окне?

Есть главное окно приложения, в нем несколько кнопок, каждая из которых должна вызывать определенный график (в новом окне). Для графика создан отдельный файл .fxml и отдельный класс Controller. При нажатии на кнопку возникает множество ошибок:

Exception in thread "JavaFX Application Thread" java.lang.ClassCastException: class java.lang.Integer cannot be cast to class java.lang.String (java.lang.Integer and java.lang.String are in module java.base of loader 'bootstrap')
at javafx.controls/javafx.scene.chart.CategoryAxis.toNumericValue(CategoryAxis.java:67)
at javafx.controls/javafx.scene.chart.LineChart.updateAxisRange(LineChart.java:206)
at javafx.controls/javafx.scene.chart.XYChart.layoutChartChildren(XYChart.java:670)
at javafx.controls/javafx.scene.chart.Chart$1.layoutChildren(Chart.java:95)
at javafx.graphics/javafx.scene.Parent.layout(Parent.java:1204)
at javafx.graphics/javafx.scene.Parent.layout(Parent.java:1211)
at javafx.graphics/javafx.scene.Parent.layout(Parent.java:1211)
at javafx.graphics/javafx.scene.Scene.doLayoutPass(Scene.java:576)
at javafx.graphics/javafx.scene.Scene.preferredSize(Scene.java:1748)
at javafx.graphics/javafx.scene.Scene$2.preferredSize(Scene.java:393)
at javafx.graphics/com.sun.javafx.scene.SceneHelper.preferredSize(SceneHelper.java:66)
at javafx.graphics/javafx.stage.Window$12.invalidated(Window.java:1086)
at javafx.base/javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:110)
at javafx.base/javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:145)
at javafx.graphics/javafx.stage.Window.setShowing(Window.java:1174)
at javafx.graphics/javafx.stage.Window.show(Window.java:1189)
at javafx.graphics/javafx.stage.Stage.show(Stage.java:273)
at javafx.graphics/javafx.stage.Stage.showAndWait(Stage.java:463)
at andelight.Controller.lambda$initialize$0(Controller.java:56)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Node.fireEvent(Node.java:8879)
at javafx.controls/javafx.scene.control.Button.fire(Button.java:200)
at javafx.controls/com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:206)
at javafx.controls/com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274)
at javafx.base/com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Scene$MouseHandler.process(Scene.java:3851)
at javafx.graphics/javafx.scene.Scene$MouseHandler.access$1200(Scene.java:3579)
at javafx.graphics/javafx.scene.Scene.processMouseEvent(Scene.java:1849)
at javafx.graphics/javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2588)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:397)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$2(GlassViewEventHandler.java:434)
at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:390)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:433)
at javafx.graphics/com.sun.glass.ui.View.handleMouseEvent(View.java:556)
at javafx.graphics/com.sun.glass.ui.View.notifyMouse(View.java:942)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
at java.base/java.lang.Thread.run(Thread.java:832)

Код Main.java файла:

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class Main extends Application {

@Override
public void start(Stage primaryStage) throws Exception{
    Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
    primaryStage.setTitle("Hello World");
    primaryStage.setScene(new Scene(root, 700, 450));
    primaryStage.show();
}


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

Код класса Controller главного окна:

public class Controller {
Logic logic = new Logic();
chart1_Controller chart1 = new chart1_Controller();

@FXML
private ResourceBundle resources;

@FXML
private URL location;

@FXML
private Button AKF1;

@FXML
private Button AKF2;

@FXML
private Button VKF;

@FXML
private Label Interval;

@FXML
private Label appTitle;

@FXML
void initialize() {
    AKF1.setOnAction(event -> {
        FXMLLoader loader = new FXMLLoader();
        loader.setLocation(getClass().getResource("/andelight/lines.fxml"));

        try {
            loader.load();
        } catch(IOException e) {
            e.printStackTrace();
        }

        Parent root = loader.getRoot();
        Stage stage = new Stage();
        stage.setScene(new Scene(root, 700, 450));
        stage.showAndWait();
    });
}
}

Код файла Controller графика:

public class chart1_Controller {

Logic temp = new Logic();

@FXML
private ResourceBundle resources;

@FXML
private URL location;

@FXML
private LineChart<Number, Number> LineChart;

@FXML
private CategoryAxis x;

@FXML
private NumberAxis y;

@FXML
void initialize() {
    XYChart.Series series1 = new XYChart.Series();
    series1.setName("02102");
    ObservableList<XYChart.Data> dataset_sin = FXCollections.observableArrayList();
    for (double i = 0; i < 20; i += 0.5) {
        dataset_sin.add(new XYChart.Data(i, Math.sin(i)));
    }
    series1.setData(dataset_sin);
    LineChart.getData().add(series1);

}
}

Код файла .fxml для графика:

<?xml version="1.0" encoding="UTF-8"?>


<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" 
prefHeight="460.0" prefWidth="792.0" xmlns="http://javafx.com/javafx/11.0.1" 
xmlns:fx="http://javafx.com/fxml/1" fx:controller="andelight.chart1_Controller">
<children>
  <LineChart fx:id="LineChart" prefHeight="460.0" prefWidth="792.0" title="АКФ 1">
    <xAxis>
      <CategoryAxis label="Время, мкс" side="BOTTOM" fx:id="x" />
    </xAxis>
    <yAxis>
      <NumberAxis fx:id="y" label="Е, В" side="LEFT" />
    </yAxis>
  </LineChart>
 </children>
</AnchorPane>