Internal graphics not initialized yet: javafx

First of all if you are using linux ,GTK 2.18 is required to run JavaFX .try to install

libswt-gtk-3-java

This exception will thrown whenever your screen is null .Try to create your images inside start method. Just before the primaryStage.show();.

Take a look at this link too

http://cr.openjdk.java.net/~vadim/RT-33475/webrev.00/modules/graphics/src/main/java/com/sun/glass/ui/Screen.java.html

I have no idea how it exactly works, but when we first create a JFXPanel in our start we don't get the errors anymore.

JFXPanel jfxPanel = new JFXPanel();