Question

Error: Main method not found in class Demo, please define the main method as:
public static void main(String[] args)
or a JavaFX application class must extend javafx.application. Application​

Answer 1

Answer:

Create a main method in java .In your class demo , create a main method as public static void main(String[] args) .else you can extend demo class to any other class which has a main method like class demo extends xyz(name of that main method containg class).