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);
}
}
The error 'Could not find or load main class' occurs when using a java command in the command prompt to launch a Java program by specifying the class name in the terminal. The reason why this happens is mostly due to the user's programming mistake while declaring the class.
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:
Install openjfx (if it is not already installed):sudo apt install openjfx
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
java --module-path $PATH_TO_OPENJFX-LIB --add-modules module_1,module_2,module_3,...,module_n -jar $PATH_TO_JAR_FILE
java --module-path /usr/share/openjfx/lib --add-modules=javafx.controls,javafx.fxml,javafx.base,javafx.media,javafx.web,javafx.swing -jar '/home/lotfi/Documents/MyAppfolder/my_application.jar'
jdk 11 does not have javafx support. Oracle removed it. But you can add javafx to your project using Maven.
I had a similar error when executing a java application, I could not find some packages already installed, I located the path where the application was reading and there I added a symbolic link to the javafx library that I had installed.
Example:
user@server:/usr/lib/jvm/java-8-openjdk-amd64/jre/lib$ sudo ln -s /usr/share/openjfx/lib/javafx.properties
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