我发现正确解决这个问题的唯一方法是使用BurningWave：

<dependency>
        <groupId>org.burningwave</groupId>
        <artifactId>core</artifactId>
        <version>12.62.6</version>
</dependency>

添加依赖项后，只需将此代码复制/粘贴到init()方法中（此方法可以-并且应该-覆盖类中的init方法，该方法扩展了Application类，这是JavaFX应用程序的入口点）

org.burningwave.core.assembler.StaticComponentContainer.Modules.exportAllToAll();
        Class<?> bootClassLoaderClass = Class.forName("jdk.internal.loader.ClassLoaders$BootClassLoader");

        Constructor<? extends ClassLoader> constructor = ClassLoader.getPlatformClassLoader().getClass().getDeclaredConstructor(bootClassLoaderClass);

        constructor.setAccessible(true);
        Class<?> classLoadersClass = Class.forName("jdk.internal.loader.ClassLoaders");

        Method bootClassLoaderRetriever = classLoadersClass.getDeclaredMethod("bootLoader");

        bootClassLoaderRetriever.setAccessible(true);

我不知道jpackage gradle任务是如何工作的，我通过控制台在jdk内部使用jpackage工具，并且在创建包时使用了此参数

--java-options "--add-opens com.gluonhq.scenebuilder.kit/com.oracle.javafx.scenebuilder.kit.util.control.paintpicker=javafx.fxml --add-opens com.gluonhq.scenebuilder.kit/com.oracle.javafx.scenebuilder.kit.util.control.paintpicker.colorpicker=javafx.fxml"

在那里，我打开PaintPicker从场景构建工具包到javafx.fxml
正如你所看到的，我必须打开两个包（实际上是五个，但放在这里太多了），你必须为每个包指定--add-opens来打开
我将使用jpackage打包应用程序的代码

jpackage.exe 
    --module-path 
        .;D:\builds\ikonlibrowser\target\ikonlibrowser.jar;
        D:\builds\ikonlibrowser\libs\icons\ikonli-antdesignicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-bootstrapicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-boxicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-bpmn-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-captainicon-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-carbonicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-codicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-coreui-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-dashicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-devicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-elusive-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-entypo-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-evaicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-feather-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-fileicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-fluentui-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-fontawesome-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-fontawesome5-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-fontelico-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-foundation-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-hawcons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-icomoon-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-ionicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-ionicons4-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-jamicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-ligaturesymbols-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-lineawesome-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-linecons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-maki-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-maki2-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-mapicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-material-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-material2-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-materialdesign-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-materialdesign2-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-medicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-metrizeicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-microns-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-ociicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-octicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-openiconic-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-paymentfont-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-prestashopicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-remixicon-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-runestroicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-simpleicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-simplelineicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-subway-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-themify-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-typicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-unicons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-weathericons-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-websymbols-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-whhg-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-win10-pack-12.2.0.jar
D:\builds\ikonlibrowser\libs\icons\ikonli-zondicons-pack-12.2.0.jar
        D:\builds\ikonlibrowser\libs\scenebuilder-kit-16.0.0.jar;
        D:\builds\ikonlibrowser\libs\jfoenix-9.0.10.jar
        D:\builds\ikonlibrowser\libs\ikonli-core-12.2.0.jar;
        D:\builds\ikonlibrowser\libs\ikonli-javafx-12.2.0.jar
    --module jcc.app.ikonlibrowser/jcc.app.ikonlibrowser.Main 
    --name "Ikonli Browser" -d D:\builds\ikonlibrowser
    --win-dir-chooser 
    --input D:\builds\ikonlibrowser\app
    --vendor jCC 
    --app-version "1.0.0"
    --java-options 
        "--add-opens com.gluonhq.scenebuilder.kit/com.oracle.javafx.scenebuilder.kit.util.control.paintpicker=javafx.fxml
        --add-opens com.gluonhq.scenebuilder.kit/com.oracle.javafx.scenebuilder.kit.util.control.paintpicker.colorpicker=javafx.fxml
        --add-opens com.gluonhq.scenebuilder.kit/com.oracle.javafx.scenebuilder.kit.util.control.paintpicker.rotator=javafx.fxml
        --add-opens com.gluonhq.scenebuilder.kit/com.oracle.javafx.scenebuilder.kit.util.control.paintpicker.slider=javafx.fxml
        --add-opens com.gluonhq.scenebuilder.kit/com.oracle.javafx.scenebuilder.kit.util.control.paintpicker.gradientpicker=javafx.fxml"

当然，这只是一条线。
现在我将一步一步地解释它：
--module-path此参数用于指定应用使用的所有模块的路径。包括应用程序.jar
--module此参数指定应用程序的主类。首先是模块名，然后是类的全名。
--name这是指定应用程序名称。
-d指定输出路径。
--win-dir-chooser在安装打包的应用程序时提供选择安装路径的选项
--input指定包含应用外部资源的文件夹
--vendor供应商的名称。也许你的名字
--app-version应用程序的版本
--java-options JVM选项
我希望这对你有用，抱歉耽搁了。