Cannot find FXML path

Question

I've done some research on the subject and still stuck. I've also searched other ways of doing it here in stack-overflow but no luck so far. I've tried without sample, moving it to another folder, nothing worked. Here's the Structure:

Main Java Code

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("sample/ui.fxml"));
    primaryStage.setScene(new Scene(root));
    primaryStage.show();
}

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

Controller.java code

package sample;

import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.text.Text;

public class Controller {

@FXML
private Text output;

@FXML
private void processNumpad(ActionEvent event){

}
@FXML
private void processOperator(ActionEvent event){

}

}

ui.fxml code

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

<?import java.net.*?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.beans.property.*?>
<?import javafx.geometry.*?>
<?import javafx.scene.shape.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.image.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.text.*?>
<?import javafx.scene.paint.Color?>

<VBox spacing="10" alignment="CENTER" prefWidth="300" prefHeight="300" fx:controller="sample.Controller" xmlns:fx="http://javafx.com/fxml">
    <fx:define>
        <Font fx:id="FONT" size="18" />
    </fx:define>

    <StackPane alignment="CENTER">
        <Rectangle fill="TRANSPARENT" stroke="GRAY" width="230" height="50" />
        <Text fx:id="output" font="$FONT" />
    </StackPane>

    <HBox spacing="10" alignment="CENTER">
        <Button text="7" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="8" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="9" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="/" prefWidth="50" font="$FONT" onAction="#processOperator" />
    </HBox>

    <HBox spacing="10" alignment="CENTER">
        <Button text="4" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="5" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="6" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="*" prefWidth="50" font="$FONT" onAction="#processOperator" />
    </HBox>

    <HBox spacing="10" alignment="CENTER">
        <Button text="1" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="2" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="3" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="-" prefWidth="50" font="$FONT" onAction="#processOperator" />
    </HBox>

    <HBox spacing="10" alignment="CENTER">
        <Button text="0" prefWidth="110" font="$FONT" onAction="#processNumpad" />
        <Button text="=" prefWidth="50" font="$FONT" onAction="#processOperator" />
        <Button text="+" prefWidth="50" font="$FONT" onAction="#processOperator" />
    </HBox>

</VBox>

Error

> Exception in Application start method
Exception in thread "main" java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException: Location is required.
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3207)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
    at sample.Main.start(Main.java:13)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    ... 1 more

I'm following this tutorial to learn more about JavaFX along with xml.

Answer 1

This is pretty close to a duplicate of:

• How to reference javafx fxml files in resource folder?

For your specific directory structure, the following will work:

getClass().getResource("ui.fxml")

The above assumes that your fxml file is actually called ui.fxml as you named it in bold in your question (note in your screenshot you have sample.fxml, so something is wrong there...).

Note, the getResource call does not need the sample/ in front of the resource file ui.fxml because the resource lookup is relative to the class location (which is already in the sample folder). If you wanted an absolute lookup rather than a relative one, you could use /sample/ui.fxml, which would also work.