fx:markupClassName attribute

The fx:markupClassName attribute controls the name of the class that contains the compiled markup of the FXML file. If this attribute is not specified, the name of the markup class defaults to the file name of the FXML document (without the file extension) and the Base suffix. For example, the default markup class name for MyControl.fxml will be MyControlBase.

The fx:markupClassName attribute can only be used when the fx:class attribute is also specified.

Usage

com/sample/MyControl.fxml

<BorderPane xmlns="http://javafx.com/javafx" xmlns:fx="http://jfxcore.org/fxml/2.0"
            fx:class="com.sample.MyControl"
            fx:markupClassName="MyCustomBaseClass">
<BorderPane/>

com/sample/MyControl.java

public class MyControl extends MyCustomBaseClass {
    MyControl() {
        initializeComponent();
    }
}