How to use FXMLLoader.load() - JavaFX 2

Due to a variety of entities eligible to be loaded through FXML you need to state the expected type yourself.

Parent page = FXMLLoader.<Parent>load(MainWindowController.class.getResource("main.fxml").toExternalForm());

Try this

Parent root= FXMLLoader.load(getClass().getResource("mention the path to your fxml file");

hope that this would help