How can I fix my IllegalStateException error?

Question

I am getting the error Caused by: java.lang.IllegalStateException: Location is not set when trying to load a new FXML file after clicking a button to navigate to another page. How can I resolve this?"

Answer 1

My guess is that this has something to do with when you are setting the root or calling the loader - you'll have to input the FXML class name exactly as a string with .fxml. For example:
FXMLLoader loader = new FXMLLoader(getClass().getResource("WelcomeScreen.fxml"));