Can't run program in command line while using LauncherImpl.launchApplication

Question

I'm doing an application and I recently add a splashscreen with LauncherImpl.launchApplication (as a preloader for my app). Before that I was able to run the program in command line and in eclipse. Now eclipse works fine but no more command line. Here is my problem : Why can ide work but not cmd line ?

I get these errors :

java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
        at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Preloader init method
        at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:896)
        at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$154(LauncherImpl.java:182)
        at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException: Location is required.
        at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3207)
        at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
        at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
        at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
        at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
        at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
        at view.MainPreloader.init(MainPreloader.java:22)
        at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:767)
        ... 2 more
Exception running application view.MainApp

Moreover eclipse says for LauncherImpl.launchApplication :

Discouraged access: The method 'LauncherImpl.launchApplication(Class, Class, String[])' is not API (restriction on required library 'C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\jfxrt.jar')

I have never seen such an error before, I found this on internet : Access restriction: The type 'Application' is not API (restriction on required library rt.jar)

But in this example I'm not sure they are using an executable jar. However I have to use one. And with an executable jar, even if I change rules as explained it doesn't work.

Help would be appreciate.

Thank you.