NullPointerException after building jar

Question

I have a JavaFX project that i develop with IntelliJ and when i run the program from there everythin works fine.

But when i run mvn clean package and try to run the jar that is built i get the following Exception:

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
        at de.application.component.main.FilterListCell.setParent(FilterListCell.java:212)
        at de.application.controller.MainController.lambda$initialize$2(MainController.java:183)
        at javafx.scene.control.skin.ListViewSkin.createCell(ListViewSkin.java:432)
        at javafx.scene.control.skin.ListViewSkin.lambda$new$9(ListViewSkin.java:207)
        at javafx.scene.control.skin.VirtualFlow.getCell(VirtualFlow.java:1672)
        at javafx.scene.control.skin.VirtualFlow.getCellLength(VirtualFlow.java:1801)
        at javafx.scene.control.skin.VirtualFlow.computeViewportOffset(VirtualFlow.java:2639)
        at javafx.scene.control.skin.VirtualFlow.layoutChildren(VirtualFlow.java:1245)
        at javafx.scene.Parent.layout(Parent.java:1204)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Parent.layout(Parent.java:1211)
        at javafx.scene.Scene.doLayoutPass(Scene.java:576)
        at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2482)
        at com.sun.javafx.tk.Toolkit.lambda$runPulse$2(Toolkit.java:412)
        at java.base/java.security.AccessController.doPrivileged(Native Method)
        at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:411)
        at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:438)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:519)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:499)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulseFromQueue(QuantumToolkit.java:492)
        at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$11(QuantumToolkit.java:320)
        at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
        at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
        at com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
        at java.base/java.lang.Thread.run(Thread.java:834)

This is the line that fails:

public void setParent(ListView<CompositeFilter> parent) {
    this.parent = parent;
    root.prefWidthProperty().bind(parent.widthProperty().subtract(16)); // this fails
}

root is being null what I don't understand because I declare it in the controler like this

    @FXML
    public AnchorPane root;

and this is the fxml file:

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

<?import javafx.geometry.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<AnchorPane fx:id="root" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity"
            minWidth="-Infinity" prefHeight="200.0" xmlns="http://javafx.com/javafx/11.0.1"
            xmlns:fx="http://javafx.com/fxml/1"
            fx:controller="de.application.component.main.FilterListCell">
  <HBox alignment="CENTER_LEFT" AnchorPane.leftAnchor="8.0" AnchorPane.topAnchor="8.0" AnchorPane.rightAnchor="8.0">
   <!-- some content -->
  </HBox>
</AnchorPane>

I have no idea why this is the case, i checked that IntelliJ uses the same JDK as i do.

Maybe this is an issue with my pom?

Here it is:

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.7.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <groupId>de.group</groupId>
  <artifactId>application</artifactId>
  <version>0.1-SNAPSHOT</version>

  <properties>
    <java.version>11</java.version>
    <javafx.version>11.0.2</javafx.version>
    <maven.compiler.plugin.version>3.8.1</maven.compiler.plugin.version>
  </properties>

  <dependencies>
    <!-- JavaFX -->
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-controls</artifactId>
      <version>${javafx.version}</version>
    </dependency>
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-fxml</artifactId>
      <version>${javafx.version}</version>
    </dependency>
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-graphics</artifactId>
      <version>${javafx.version}</version>
    </dependency>
    <dependency>
      <groupId>org.openjfx</groupId>
      <artifactId>javafx-base</artifactId>
      <version>${javafx.version}</version>
    </dependency>

    <dependency>
      <groupId>org.controlsfx</groupId>
      <artifactId>controlsfx</artifactId>
      <version>11.0.1</version>
    </dependency>
    <!-- Spring Boot -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
    </dependency>

    <!-- Other -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.module</groupId>
      <artifactId>jackson-module-parameter-names</artifactId>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.datatype</groupId>
      <artifactId>jackson-datatype-jdk8</artifactId>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.datatype</groupId>
      <artifactId>jackson-datatype-jsr310</artifactId>
    </dependency>

    <dependency>
      <groupId>net.rgielen</groupId>
      <artifactId>javafx-weaver-spring</artifactId>
      <version>1.2.0</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-configuration-processor</artifactId>
      <optional>true</optional>
    </dependency>

    <!-- Test -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>${maven.compiler.plugin.version}</version>
        <configuration>
          <source>${java.version}</source>
          <target>${java.version}</target>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>

</project>

All help will be greatly appreciated.

EDIT

The code snippet from the MainController is this

lstFilter.setCellFactory(compositeFilterListView -> {
            FxControllerAndView<FilterListCell, Node> cell = fxWeaver.load(FilterListCell.class);
            if(cell.getView().isPresent()) {
                cell.getView().get().setVisible(false);
                cell.getController().setGraphic(cell.getView().get());
            }
            cell.getController().setParent(lstFilter); // setParent fails
            return cell.getController();
        });

This is just a CellFactory for the Listview lstFilter. The real problem is the discrepency between running through Intellij, where this error does not occur and running the built jar trough the command line, where this fails.

score 1 · Accepted Answer · answered May 04 '20 at 12:23

1

So I figured out a solution to my problem:

The prolem was that my fxml file was not found. I am still not sure why. The controller class was called FilterListView and my fxml file filterListView.fxml. Now i renamed the fxml file to FilterListView.fxml and it works.

Does anyone know why the classpath seems to be case-sensitive when running a jar and not case-sensitive when running from the IDE?

answered May 04 '20 at 12:23

Amir Schnell

611
4
11

2

If you're running from the file system (i.e. the classpath is an actual folder on the file system), then the `ClassLoader` will look for resources by looking for files matching the file name in a folder matching the package structure. If you're running on a brain-dead operating system that ignores case in filenames, it will work with the wrong file name. When you run from a jar file, then the jar `ClassLoader` looks for an entry in the jar file matching the name of the resource, which of course is case sensitive. – James_D May 04 '20 at 12:27
1

See https://stackoverflow.com/questions/61531317/how-do-i-determine-the-correct-path-for-fxml-files-css-files-images-and-other for more general info on looking up FXML files and other resources by resource name. – James_D May 04 '20 at 12:28

NullPointerException after building jar

1 Answers1