Error in validation of JFXTextField - javafx

Question

This is my first JavaFX program and I want to accept the username via eUser and password via ePass. When I try to check if the textfield is empty using validate I get this error:
Exception in Application start method
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$154(LauncherImpl.java:182)
at java.lang.Thread.run(Thread.java:748)
Caused by: javafx.fxml.LoadException:
file:/Users/dylan/NetBeansProjects/JavaFXApplication2/dist/run350595374/JavaFXApplication2.jar!/javafxapplication2/FXMLDocument.fxml
at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2579)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
at javafxapplication2.JavaFXApplication2.start(JavaFXApplication2.java:23)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
Caused by: java.lang.NullPointerException
at javafxapplication2.FXMLDocumentController.initialize(FXMLDocumentController.java:48)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
... 14 more
Exception running application javafxapplication2.JavaFXApplication2
Java Result: 1
When I comment out eUser.getValidators().add(vali); from Controller.java file and the lines that follow it, then no errors show up.
This is my FXMLDocumentController.java file:
public class FXMLDocumentController implements Initializable {
#FXML
private JFXTextField eUser;
#FXML
private JFXTextField ePass;
#FXML
private void handleClose(MouseEvent event) {
System.exit(0);
}
#Override
public void initialize(URL url, ResourceBundle rb) {
RequiredFieldValidator vali = new RequiredFieldValidator();
eUser.getValidators().add(vali);
vali.setMessage("No Input Given");
vali.focusedProperty().addListener(new ChangeListener<Boolean>(){
public void changed(ObservableValue<? extends Boolean> observable, Boolean oldValue, Boolean newValue) {
if(!newValue)
{
eUser.validate();
}
}});}}
Main class:
public class JavaFXApplication2 extends Application {
#Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));
stage.initStyle(StageStyle.UNDECORATED);
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}

Answer 1

Maybe this could be the problem. In your FXML file, check if you set those ID's to the relevant textfields. That might possibly be the thing which is causing the NullPointerException.
If you're using SceneBuilder, click on the relevant textfield -> Code and set the fx:id of those textFields.
And by the way, you can probably use a PasswordField instead of a TextField :)