Error: Could not find or load main class application.Main Caused by: java.lang.NoClassDefFoundError: javafx/application/Application JDK 11

Question

I am stuck at a very basic problem. I have created a simple hello world program using JavaFX which works fine on JDK 1.8. But when I switch to JDK-11 it throws following exception:

Error: Could not find or load main class application.Main
Caused by: java.lang.NoClassDefFoundError: javafx/application/Application

Following is the code I wrote in eclipse.

package application;

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


public class Main extends Application {

    private Scene theScene;
    @Override
    public void start(Stage primaryStage) {
try {

            FXMLLoader loader = new FXMLLoader(getClass().getResource("MyScene.fxml"));
            Parent mainPane = loader.load();


            theScene = new Scene(mainPane);
            primaryStage.setScene(theScene);
            primaryStage.show();

        } catch(Exception e) {
            e.printStackTrace();
        }
    }

    public void setTheScene(Scene theScene) {
        this.theScene = theScene;
    }

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

Answer 1

I faced the same issue on debian after upgrading from stretch to buster, but now, everything is fine:

java --version

openjdk 11.0.4 2019-07-16

To run a java-fx application using terminal, follow these steps:

1. Install openjfx (if it is not already installed):
   sudo apt install openjfx

2. List the javafx library location:
   dpkg-query -L openjfx
   The output should be like this:

. /usr /usr/share /usr/share/doc /usr/share/doc/openjfx /usr/share/doc/openjfx/TODO.Debian /usr/share/doc/openjfx/changelog.Debian.gz /usr/share/doc/openjfx/copyright /usr/share/openjfx /usr/share/openjfx/lib /usr/share/openjfx/lib/javafx.properties /usr/share/openjfx/lib/javafx.base.jar /usr/share/openjfx/lib/javafx.controls.jar /usr/share/openjfx/lib/javafx.fxml.jar /usr/share/openjfx/lib/javafx.graphics.jar /usr/share/openjfx/lib/javafx.media.jar /usr/share/openjfx/lib/javafx.swing.jar /usr/share/openjfx/lib/javafx.web.jar

3. Run the jar application by including the javafx path and modules :
   java --module-path $PATH_TO_OPENJFX-LIB --add-modules module_1,module_2,module_3,...,module_n -jar $PATH_TO_JAR_FILE

Example:

java --module-path /usr/share/openjfx/lib --add-modules=javafx.controls,javafx.fxml,javafx.base,javafx.media,javafx.web,javafx.swing -jar '/home/lotfi/Documents/MyAppfolder/my_application.jar'

Answer 2

jdk 11 does not have javafx support. Oracle removed it. But you can add javafx to your project using Maven.

Answer 3

In Eclipse : run configurations -> arguments -> VM arguments :

--module-path ${project_classpath:REPLACE_ME_WITH_YOUR_PROJECT_NAME} 

--add-modules javafx.controls,javafx.fxml

Answer 4

I had a similar error when executing a java application, I could not find some packages already installed, I located the path where the application was reading and there I added a symbolic link to the javafx library that I had installed.

Example:

user@server:/usr/lib/jvm/java-8-openjdk-amd64/jre/lib$ sudo ln -s /usr/share/openjfx/lib/javafx.properties