Vfrdtyky

I have a controller that receives data from another(login page) through loading it's fxml

fxmlLoader = new FXMLLoader(UserMainController.class.getResource("FXMLDocument.fxml"));



                //User

                Parent userParent = (Parent) fxmlLoader.load();

                userController = fxmlLoader.<UserMainController>getController();

                userController.setUser(userID, collegeID, username, password, key);

                Scene userScene = new Scene(userParent);



                //get stage information

                Stage window = (Stage) ((Node)event.getSource()).getScene().getWindow();



                window.setScene(userScene);

                window.show();

this is working fine.
Inside the controller of FXMLDocument.fxml(the one i'm loading above), i'm trying to pass it's instance to other controllers

@Override

public void initialize(URL url, ResourceBundle rb) {

        tab1.init(this);

        tab2.init(this);

        tab3.init(this);

}

and also inside the fxml of FXMLDocument.fxml, they are included like this

                       <BorderPane fx:id="tab1BP">

                       <center>

                           <fx:include fx:id="tab1" source="Tab1/tab1.fxml"/>

                       </center></BorderPane>







                         <BorderPane fx:id="tab2BP" prefHeight="200.0" prefWidth="200.0">

                         <center>

                             <fx:include fx:id="tab2" source="Tab2/tab2.fxml"/>

                         </center></BorderPane>







                         <BorderPane fx:id="tab3BP">

                         <center>

                             <fx:include fx:id="tab3" source="Tab3/tab3.fxml"/>

                         </center>

                         </BorderPane>

I'm getting an error at the line tab3.init(this);

Caused by: java.lang.NullPointerException

at ara_thesis.User.UserMainController.initialize(UserMainController.java:149)

at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)

... 61 more

and tab3's initialize function looks like this

@Override

public void initialize(URL url, ResourceBundle rb) {

    Platform.runLater(() -> {

        this.user = userMainController.getUser();

        try {

            initializeProgramTable();

        } catch (SQLException ex) {

            Logger.getLogger(CourseSectionController.class.getName()).log(Level.SEVERE, null, ex);

        }

    });

it returns null at the line 149 that is
this.user = userMainController.getUser(); (which is a function inside UserMainController that gets data that came from the login controller.)

and also after trying the built in debugger for netbeans, i found out that tab1.init(this) and tab3.init(this) contains they're controller's instance, as there is a value shown when I hovered above it, and null for tab2.init(this). Removing tab2.init(this) and removing it's inclusion inside the fxml file would result to no errors, so that gave me the conclusion that tab3 is the one with error. But I can't seem to find it. Enclosing tab1.init......tab3.init(this); inside a Platform.runLater would also result to null pointer exception as tab3.initialize would look for a value that would be coming from the usermaincontroller.
Am I missing something here? Thank you for the help