Can JavaFX realistically be used in a non-modular environment?

I’ve attempted to use JavaFX by following instructions found at:

https://openjfx.io/openjfx-docs/ under “JavaFX and IntelliJ” -> “Non-modular with Maven”

After completing steps 1 & 2 (Installation & Verification) I attempted to run a very simple program from IntelliJ rather than through the Maven plugin.

TraderWindow.java

public class TraderWindow extends Application {

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

    @Override
    @SneakyThrows
    public void start(Stage primaryStage) {
        Scene scene = FXMLLoader.load(getClass().getResource("/TraderWindow.fxml"));
        primaryStage.setScene(scene);
        primaryStage.show();
    }
}

TraderWindow.fxml

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

<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<GridPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/10.0.2-internal" xmlns:fx="http://javafx.com/fxml/1">
  <columnConstraints>
    <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
    <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
  </columnConstraints>
  <rowConstraints>
    <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
    <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
    <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
  </rowConstraints>
   <children>
      <Button mnemonicParsing="false" text="Button" />
   </children>
</GridPane>

However when I attempted to run it I got:

java.lang.reflect.InvocationTargetException
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:464)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:363)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at java.base/sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:1051)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:900)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(LauncherImpl.java:195)
    at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.lang.IllegalAccessError: class com.sun.javafx.fxml.FXMLLoaderHelper (in unnamed module @0x6adc19e3) cannot access class com.sun.javafx.util.Utils (in module javafx.graphics) because module javafx.graphics does not export com.sun.javafx.util to unnamed module @0x6adc19e3
    at com.sun.javafx.fxml.FXMLLoaderHelper.<clinit>(FXMLLoaderHelper.java:38)
    at javafx.fxml.FXMLLoader.<clinit>(FXMLLoader.java:2138)
    at com.trader.gui.TraderWindow.start(TraderWindow.java:19)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:846)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:474)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:447)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:446)
    at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
    ... 1 more
Exception running application com.trader.gui.TraderWindow

Process finished with exit code 1

The relevant part:

Caused by: java.lang.IllegalAccessError: class com.sun.javafx.fxml.FXMLLoaderHelper (in unnamed module @0x6adc19e3) cannot access class com.sun.javafx.util.Utils (in module javafx.graphics) because module javafx.graphics does not export com.sun.javafx.util to unnamed module @0x6adc19e3

Which, I guess, is understandable since JafaFx is modularized and my application is not. In order to circumvent the problem I added this to VM path:

--add-opens javafx.graphics/com.sun.javafx.util=ALL-UNNAMED

I tried again, this time getting:

Caused by: java.lang.IllegalAccessError: class javafx.fxml.JavaFXBuilderFactory (in unnamed module @0x4e342850) cannot access class com.sun.javafx.reflect.ConstructorUtil (in module javafx.base) because module javafx.base does not export com.sun.javafx.reflect to unnamed module @0x4e342850

And so I added another –add-opens directive… And then I repeated these steps 3 more times before giving up.

Is there another way of making JavaFX work with Java 11+ rather than modularizing the application or painstakingly adding --add-opens directives for each and every illegal access operation?

Answer

If you completely want to get rid of all this module system trouble you could add a line like this to your main class

class MyAppLauncher {public static void main(String[] args) {MyApp.main(args);}}

and then launch the app via this launcher. If you do that you can put everything on the classpath and remove all -add-opens. (actually you have to.) The only drawback is that since JavaFX 16 you will get a nasty warning message saying Unsupported JavaFX configuration but you can just ignore that.

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Answer