Default controller not work with my fxml - eclipse

Question

I have no clue why this code does not work. I have created an fxml document using Scene Builder and all it does is add a borderpane. So far I only get errors when trying to call my fxml. I think it might be because the program dose not think I initialized some of my variables, but I don;t know why.
import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.fxml.FXMLLoader;
public class Main extends Application {
#Override
public void start(Stage primaryStage) {
try {
BorderPane root = (BorderPane)FXMLLoader.load(getClass().getResource("Sample.fxml"));
Scene scene = new Scene(root,400,400);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show();
} catch(Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
launch(args);
}
}
import javafx.fxml.FXML;
import javafx.scene.layout.Pane;
public class SampleController {
#FXML
Pane mainPane;
#FXML
private void initialize() {
System.out.println(mainPane.getHeight());
}
}
hears the fxml file created.
<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.Menu?>
<?import javafx.scene.control.MenuBar?>
<?import javafx.scene.control.MenuItem?>
<?import javafx.scene.control.ScrollPane?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.BorderPane?>
<?import javafx.scene.layout.Pane?>
<?import javafx.scene.layout.VBox?>
<?import javafx.scene.text.Font?>
<BorderPane maxHeight="-Infinity" minHeight="-Infinity" minWidth="-Infinity" xmlns="http://javafx.com/javafx/8.0.141" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.SampleController">
<top>
<MenuBar BorderPane.alignment="CENTER">
<menus>
<Menu mnemonicParsing="false" text="File">
<items>
<MenuItem mnemonicParsing="false" text="Close" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Edit">
<items>
<MenuItem mnemonicParsing="false" text="Delete" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Help">
<items>
<MenuItem mnemonicParsing="false" text="About" />
</items>
</Menu>
</menus>
</MenuBar>
</top>
<center>
<BorderPane prefHeight="200.0" BorderPane.alignment="CENTER">
<center>
<AnchorPane prefHeight="273.0" prefWidth="1104.0" BorderPane.alignment="CENTER">
<children>
<Pane fx:id="taskPane" layoutX="10.0" layoutY="4.0" minHeight="259.0" AnchorPane.bottomAnchor="10.0" AnchorPane.topAnchor="0.0">
<children>
<ScrollPane layoutX="19.0" layoutY="54.0" prefHeight="205.0" prefWidth="337.0">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="235.0" prefWidth="290.0">
<children>
<VBox layoutX="1.0" prefHeight="238.0" prefWidth="297.0" />
</children>
</AnchorPane>
</content>
</ScrollPane>
<Button layoutX="39.0" layoutY="16.0" mnemonicParsing="false" text="New Habit" />
<Label layoutX="152.0" layoutY="21.0" text="Habits">
<font>
<Font size="22.0" />
</font>
</Label>
</children>
</Pane>
<Pane layoutX="376.0" layoutY="7.0" minHeight="259.0" AnchorPane.bottomAnchor="10.0" AnchorPane.topAnchor="0.0">
<children>
<ScrollPane layoutX="19.0" layoutY="54.0" prefHeight="205.0" prefWidth="337.0">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="235.0" prefWidth="290.0">
<children>
<VBox layoutX="1.0" prefHeight="238.0" prefWidth="297.0" />
</children>
</AnchorPane>
</content>
</ScrollPane>
<Button layoutX="39.0" layoutY="16.0" mnemonicParsing="false" text="New Task" />
<Label layoutX="152.0" layoutY="21.0" text="Dayley Tasks">
<font>
<Font size="22.0" />
</font>
</Label>
</children>
</Pane>
<Pane layoutX="748.0" layoutY="15.0" minHeight="259.0" prefHeight="259.0" prefWidth="356.0" AnchorPane.bottomAnchor="20.0" AnchorPane.topAnchor="0.0">
<children>
<ScrollPane layoutX="19.0" layoutY="54.0" prefHeight="205.0" prefWidth="337.0">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="235.0" prefWidth="290.0">
<children>
<VBox layoutX="1.0" prefHeight="238.0" prefWidth="297.0" />
</children>
</AnchorPane>
</content>
</ScrollPane>
<Button layoutX="39.0" layoutY="16.0" mnemonicParsing="false" text="New ToDo" />
<Label layoutX="152.0" layoutY="21.0" text="To Do List">
<font>
<Font size="22.0" />
</font>
</Label>
</children>
</Pane>
</children>
<padding>
<Insets bottom="10.0" />
</padding>
</AnchorPane>
</center>
<top>
<Pane prefHeight="150.0" prefWidth="400.0" BorderPane.alignment="CENTER" />
</top>
<BorderPane.margin>
<Insets left="10.0" right="10.0" top="10.0" />
</BorderPane.margin>
</BorderPane>
</center>
</BorderPane>
this is what my project looks like.
[enter image description here][1]
[Main (3) [Java Application]
application.Main at localhost:34867
Thread [main] (Suspended (exception NullPointerException))
SystemProperties.setVersions() line: 81
SystemProperties.lambda$static$55() line: 67
1917513796.run() line: not available
AccessController.doPrivileged(PrivilegedAction<T>) line: not available [native method]
SystemProperties.<clinit>() line: 64
LauncherImpl.startToolkit() line: 668
LauncherImpl.launchApplicationWithArgs(String, String, String[]) line: 337
LauncherImpl.launchApplication(String, String, String[]) line: 328
NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]
NativeMethodAccessorImpl.invoke(Object, Object[]) line: 62
DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 43
Method.invoke(Object, Object...) line: 498
LauncherHelper$FXHelper.main(String...) line: 767
/usr/lib/jvm/java-8-openjdk-amd64/bin/java (Mar 24, 2018, 5:19:54 PM)
][2]
[1]: https://i.stack.imgur.com/ThjM6.png
[2]: http://eror.com

Answer 1

I think I have fixed it try replacing your fxml with this
<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.Menu?>
<?import javafx.scene.control.MenuBar?>
<?import javafx.scene.control.MenuItem?>
<?import javafx.scene.control.ScrollPane?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.BorderPane?>
<?import javafx.scene.layout.Pane?>
<?import javafx.scene.layout.VBox?>
<?import javafx.scene.text.Font?>
<BorderPane maxHeight="-Infinity" minHeight="-Infinity" minWidth="-Infinity" xmlns="http://javafx.com/javafx/8.0.141" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.SampleController">
<top>
<MenuBar BorderPane.alignment="CENTER">
<menus>
<Menu mnemonicParsing="false" text="File">
<items>
<MenuItem mnemonicParsing="false" text="Close" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Edit">
<items>
<MenuItem mnemonicParsing="false" text="Delete" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Help">
<items>
<MenuItem mnemonicParsing="false" text="About" />
</items>
</Menu>
</menus>
</MenuBar>
</top>
<center>
<BorderPane prefHeight="200.0" BorderPane.alignment="CENTER">
<center>
<AnchorPane prefHeight="273.0" prefWidth="1104.0" BorderPane.alignment="CENTER">
<children>
<Pane fx:id="taskPane" layoutX="10.0" layoutY="4.0" minHeight="259.0" AnchorPane.bottomAnchor="10.0" AnchorPane.topAnchor="0.0">
<children>
<ScrollPane layoutX="19.0" layoutY="54.0" prefHeight="205.0" prefWidth="337.0">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="235.0" prefWidth="290.0">
<children>
<VBox layoutX="1.0" prefHeight="238.0" prefWidth="297.0" />
</children>
</AnchorPane>
</content>
</ScrollPane>
<Button layoutX="39.0" layoutY="16.0" mnemonicParsing="false" text="New Habit" />
<Label layoutX="152.0" layoutY="21.0" text="Habits">
<font>
<Font size="22.0" />
</font>
</Label>
</children>
</Pane>
<Pane layoutX="376.0" layoutY="7.0" minHeight="259.0" AnchorPane.bottomAnchor="10.0" AnchorPane.topAnchor="0.0">
<children>
<ScrollPane layoutX="19.0" layoutY="54.0" prefHeight="205.0" prefWidth="337.0">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="235.0" prefWidth="290.0">
<children>
<VBox layoutX="1.0" prefHeight="238.0" prefWidth="297.0" />
</children>
</AnchorPane>
</content>
</ScrollPane>
<Button layoutX="39.0" layoutY="16.0" mnemonicParsing="false" text="New Task" />
<Label layoutX="152.0" layoutY="21.0" text="Dayley Tasks">
<font>
<Font size="22.0" />
</font>
</Label>
</children>
</Pane>
<Pane layoutX="748.0" layoutY="15.0" minHeight="259.0" prefHeight="259.0" prefWidth="356.0" AnchorPane.bottomAnchor="20.0" AnchorPane.topAnchor="0.0">
<children>
<ScrollPane layoutX="19.0" layoutY="54.0" prefHeight="205.0" prefWidth="337.0">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="235.0" prefWidth="290.0">
<children>
<VBox layoutX="1.0" prefHeight="238.0" prefWidth="297.0" />
</children>
</AnchorPane>
</content>
</ScrollPane>
<Button layoutX="39.0" layoutY="16.0" mnemonicParsing="false" text="New ToDo" />
<Label layoutX="152.0" layoutY="21.0" text="To Do List">
<font>
<Font size="22.0" />
</font>
</Label>
</children>
</Pane>
</children>
<padding>
<Insets bottom="10.0" />
</padding>
</AnchorPane>
</center>
<top>
<Pane fx:id="mainPane" prefHeight="150.0" prefWidth="400.0" BorderPane.alignment="CENTER" />
</top>
<BorderPane.margin>
<Insets left="10.0" right="10.0" top="10.0" />
</BorderPane.margin>
</BorderPane>
</center>