Получение исключения в потоке java .lang.RuntimeException: java .lang.reflect.InvocationTargetException при изменении сцены на той же стадии

Question

Я хочу изменить сцену на том же этапе с mainPage.f xml на logIn.f xml, но я получаю ошибку (java .lang.RuntimeException: java .lang .reflect.InvocationTargetException) . Может ли кто-нибудь помочь мне, пожалуйста ..., я пытался много раз, но я не могу найти решение этого .. вот мой код

Main. java

package sample;

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("mainPage.fxml"));
        primaryStage.setTitle("Hello World");
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }


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

Контроллер . java

package sample;

import javafx.event.ActionEvent;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Stage;

import java.io.IOException;

import static javafx.fxml.FXMLLoader.load;

public class Controller {

    public AnchorPane mP;

    public void student(ActionEvent actionEvent) {

    }

    public void library(ActionEvent actionEvent) {
    }

    public void finance(ActionEvent actionEvent) {
    }

    public void admin(ActionEvent actionEvent) throws IOException {

        Parent newroot = FXMLLoader.load(getClass().getClassLoader().getResource("logIn.fxml"));
        Stage stage = (Stage) mP.getScene().getWindow();
        stage.setScene(new Scene(newroot));
        stage.show();


    }
}

mainPage.f xml

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

<?import javafx.scene.control.Button?>
<?import javafx.scene.image.Image?>
<?import javafx.scene.image.ImageView?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.layout.Pane?>
<?import javafx.scene.layout.RowConstraints?>

<AnchorPane fx:id="mP" prefHeight="602.0" prefWidth="753.0" style="-fx-background-color: white;" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
   <children>
      <Pane fx:id="student" layoutX="-1.0" prefHeight="174.0" prefWidth="753.0" style="-fx-background-color: #617be3;" />
      <GridPane alignment="CENTER" layoutX="125.0" layoutY="216.0" prefHeight="339.0" prefWidth="501.0">
         <columnConstraints>
            <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
            <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
         </columnConstraints>
         <rowConstraints>
            <RowConstraints maxHeight="270.0" minHeight="10.0" prefHeight="218.0" vgrow="SOMETIMES" />
            <RowConstraints maxHeight="374.0" minHeight="0.0" prefHeight="220.0" vgrow="SOMETIMES" />
         </rowConstraints>
         <children>
            <Button alignment="CENTER" contentDisplay="CENTER" mnemonicParsing="false" onAction="#student" prefHeight="272.0" prefWidth="251.0" style="-fx-background-color: white;" textAlignment="CENTER">
               <graphic>
                  <ImageView fitHeight="150.0" fitWidth="200.0" pickOnBounds="true" preserveRatio="true">
                     <image>
                        <Image url="@Icons/student.png" />
                     </image>
                  </ImageView>
               </graphic></Button>
            <Button alignment="CENTER" contentDisplay="CENTER" mnemonicParsing="false" onAction="#library" prefHeight="272.0" prefWidth="251.0" style="-fx-background-color: white;" GridPane.columnIndex="1">
               <graphic>
                  <ImageView fitHeight="150.0" fitWidth="200.0" pickOnBounds="true" preserveRatio="true">
                     <image>
                        <Image url="@Icons/library.png" />
                     </image>
                  </ImageView>
               </graphic>
            </Button>
            <Button alignment="CENTER" contentDisplay="CENTER" mnemonicParsing="false" onAction="#finance" prefHeight="272.0" prefWidth="251.0" style="-fx-background-color: white;" GridPane.rowIndex="1">
               <graphic>
                  <ImageView fitHeight="150.0" fitWidth="200.0" pickOnBounds="true" preserveRatio="true">
                     <image>
                        <Image url="@Icons/finance.png" />
                     </image>
                  </ImageView>
               </graphic>
            </Button>
            <Button alignment="CENTER" contentDisplay="CENTER" mnemonicParsing="false" onAction="#admin" prefHeight="272.0" prefWidth="251.0" style="-fx-background-color: white;" GridPane.columnIndex="1" GridPane.rowIndex="1">
               <graphic>
                  <ImageView fitHeight="150.0" fitWidth="200.0" pickOnBounds="true" preserveRatio="true">
                     <image>
                        <Image url="@Icons/admin.png" />
                     </image>
                  </ImageView>
               </graphic>
            </Button>
         </children>
      </GridPane>
   </children>
</AnchorPane>

logIn.f xml

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

<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.Pane?>

<AnchorPane prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.LogIn">
   <children>
      <Pane layoutX="-2.0" layoutY="-2.0" prefHeight="119.0" prefWidth="600.0" style="-fx-background-color: blue;" />
      <Label layoutX="121.0" layoutY="192.0" style="-fx-font-size: 20px;" text="Username" />
      <TextField fx:id="username" layoutX="315.0" layoutY="188.0" />
      <Label layoutX="121.0" layoutY="262.0" style="-fx-font-size: 20px;" text="Password" />
      <TextField fx:id="password" layoutX="315.0" layoutY="258.0" />
      <Button layoutX="252.0" layoutY="330.0" mnemonicParsing="false" style="-fx-background-color: #4CAF50; -fx-border-color: white; -fx-padding: 10px 20px; -fx-text-alignment: center; -fx-font-size: 15;" text="LogIn" />
   </children>
</AnchorPane>

Ошибка

"C:\Program Files\Java\jdk-11.0.3\bin\java.exe" --add-modules javafx.base,javafx.graphics --add-reads javafx.base=ALL-UNNAMED --add-reads javafx.graphics=ALL-UNNAMED "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2019.3.1\lib\idea_rt.jar=59741:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2019.3.1\bin" -Dfile.encoding=UTF-8 -p C:\Users\tyagi\OneDrive\Documents\javafx-sdk-11.0.2\lib\javafx.base.jar;C:\Users\tyagi\OneDrive\Documents\javafx-sdk-11.0.2\lib\javafx.graphics.jar;C:\Users\tyagi\IdeaProjects\HelloWorldFXl\out\production\HelloWorldFX;C:\Users\tyagi\OneDrive\Documents\javafx-sdk-11.0.2\lib\javafx-swt.jar;C:\Users\tyagi\OneDrive\Documents\javafx-sdk-11.0.2\lib\javafx.controls.jar;C:\Users\tyagi\OneDrive\Documents\javafx-sdk-11.0.2\lib\javafx.fxml.jar;C:\Users\tyagi\OneDrive\Documents\javafx-sdk-11.0.2\lib\javafx.media.jar;C:\Users\tyagi\OneDrive\Documents\javafx-sdk-11.0.2\lib\javafx.swing.jar;C:\Users\tyagi\OneDrive\Documents\javafx-sdk-11.0.2\lib\javafx.web.jar -m HelloWorldFX/sample.Main
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at javafx.fxml/javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1787)
    at javafx.fxml/javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1670)
    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(Native Method)
    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$3(WinApplication.java:174)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.reflect.InvocationTargetException
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at com.sun.javafx.reflect.Trampoline.invoke(MethodUtil.java:76)
    at jdk.internal.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at javafx.base/com.sun.javafx.reflect.MethodUtil.invoke(MethodUtil.java:273)
    at javafx.fxml/com.sun.javafx.fxml.MethodHelper.invoke(MethodHelper.java:83)
    at javafx.fxml/javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1782)
    ... 47 more
Caused by: java.lang.NullPointerException: Location is required.
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3230)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3194)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3163)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3136)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3113)
    at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:3106)
    at HelloWorldFX/sample.Controller.admin(Controller.java:30)
    ... 58 more

Process finished with exit code 0

Я просто хочу переключаться между несколькими сценами на одной сцене. Заранее спасибо за помощь ...