Problemas em criar telas no JavaFx

Programação
#1

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Stage;

public class Login extends Application {

private AnchorPane pane;
private TextField txLogin ;
private PasswordField txSenha;
private Button btEntrar, btSair;
private static Stage stage;




public static Stage getStage() {
return stage;

}

private void initComponents() {

AnchorPane pane= new AnchorPane();
pane.setPrefSize(400, 300);

TextField txLogin = new TextField();
txLogin.setPromptText("Digite aqui seu login:");

PasswordField txSenha= new PasswordField();
txSenha.setPromptText("Digite aqui sua senha");

Button btEntrar= new Button();
Button btSair= new Button();

pane.getChildren().addAll(txLogin, txSenha, btEntrar, btSair);

}

private void initLayout() {

txLogin.setLayoutX((pane.getWidth()-txLogin.getWidth())/2);
txLogin.setLayoutY(50);
		
txSenha.setLayoutX((pane.getWidth()-txSenha.getWidth())/2);
txSenha.setLayoutY(100);
		
btEntrar.setLayoutX((pane.getWidth()-btEntrar.getWidth())/2);
btEntrar.setLayoutY(150);
		
btSair.setLayoutX(btSair.getWidth()+ btEntrar.getLayoutX()+35);
btSair.setLayoutY(150);

pane.setStyle("-fx-background-color: linear-gradient( from 0% 0% to 100% 100%, blue 0%, silver 100%)");

}

@Override
public void start(Stage stage) throws Exception {

initComponents();
Scene scene= new Scene(pane);
stage.setScene(scene);	
stage.show();
initLayout();
Login.stage=stage;

}

public static void main (String[]args) {

launch(args);

}

}

ERRO:

Exception in Application start method
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
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(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$154(LauncherImpl.java:182)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException: Children: child node is null: parent = AnchorPane@79c2135c
at javafx.scene.Parent$2.onProposedChange(Parent.java:435)
at com.sun.javafx.collections.VetoableListDecorator.addAll(VetoableListDecorator.java:234)
at com.sun.javafx.collections.VetoableListDecorator.addAll(VetoableListDecorator.java:103)
at Login.initComponents(Login.java:48)
at Login.start(Login.java:23)
at com.sun.javafx.application.LauncherImpl.lambda$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)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
… 1 more
Exception running application Login

#2

já resolvi mudando o método initComponents para :
private void initComponents() {

pane= new AnchorPane();
pane.setPrefSize(400, 300);

txLogin = new TextField();
txLogin.setPromptText("Digite aqui seu login:");

txSenha= new PasswordField();
txSenha.setPromptText("Digite aqui sua senha");

 btEntrar= new Button("Entrar");
 btSair= new Button("Sair");

pane.getChildren().addAll(txLogin, txSenha, btEntrar, btSair);

}