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I know this question has been asked many times, half of them its probably caused by forgetting to check the variable names. Have done that even bounced all over different tutorials to find different solutions. Am trying to verify TextField with postgres database so the user can login. If I comment out the password field the code runs and I can get the user name in the console. When I run PasswordField.getText() I get the NullPointerException error. Tried cleaning workspace and recaching nohing worked, the code ran fine before I used scene builder and now not so much. If anyone has any pointers please feel free to share been having a headache for the past week over this and not made much progress :( Edit: Added detailed parts of the file and the stacktrace

Main App.java file

package com.schoolAdmin.app;


import javafx.application.Application;
import javafx.event.*;
import javafx.scene.*;
import javafx.stage.Stage;
import java.sql.SQLException;
import javafx.fxml.*;
import java.net.URL;

import com.schoolAdmin.controllers.DependancyInjector;
import com.schoolAdmin.controllers.LoginFXML;
import com.schoolAdmin.psql.Postgres;
import com.schoolAdmin.scenes.Records_Display;

public class App extends Application {
    
    Postgres psql = new Postgres();
    
    
    @Override
    public void start(Stage stage) throws Exception {
        
        Parent root = FXMLLoader.load(getClass().getResource("../fxml/login_screen.fxml"));

        Scene loginScene = new Scene(root)

        stage.setScene(loginScene);

        stage.setResizable(true);
        stage.setTitle("Welcome Screen");
        stage.show();
    }

    public static void main(String[] args) {
        Postgres.main(args);
        launch();
    }

}

Controller file for login_Screen.fxml

import javafx.fxml.*;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.stage.*;
import javafx.event.*;
import java.net.URL;
import java.util.ResourceBundle;

import com.schoolAdmin.modals.AlertModule;
import com.schoolAdmin.psql.Postgres;

import javafx.scene.layout.*;
import javafx.scene.text.*;

public class LoginFXML{
    @FXML
    private TextField userField; 
    private PasswordField passField;

    @FXML
    private URL location;

    @FXML
    private ResourceBundle resources;

    @FXML
    private Button subBtn;

    @FXML
    private void subKey(ActionEvent event) throws Exception{

        // userField = new TextField();
        // passField = new PasswordField();
        // System.out.println(passField.getText().toString());
        Postgres psql = new Postgres();
        boolean val=psql.validate(userField.getText(), passField.getText());
        if(val){
            System.out.println(val + "User Authenticated");
        } else {
            System.out.println("Failed To Authenticate");
        }

    }

    @FXML
    void initialize(){
    }

    public String getUser(){
        return this.userField.getText();
    }

}

This is the FXML file from scene builder

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.PasswordField?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.image.Image?>
<?import javafx.scene.image.ImageView?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.layout.TilePane?>
<?import javafx.scene.layout.VBox?>
<?import javafx.scene.text.Font?>
<?import javafx.scene.text.Text?>

<VBox id="VBOX_Parent" alignment="CENTER" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="550.0" prefWidth="840.0" xmlns="http://javafx.com/javafx/16" xmlns:fx="http://javafx.com/fxml/1" fx:controller="com.schoolAdmin.controllers.LoginFXML">
   <children>
      <Text strokeType="OUTSIDE" strokeWidth="0.0" text="Login" textAlignment="CENTER">
         <font>
            <Font name="Times New Roman" size="36.0" />
         </font>
         <VBox.margin>
            <Insets bottom="30.0" />
         </VBox.margin>
      </Text>
      <ImageView fitHeight="257.0" fitWidth="295.0" pickOnBounds="true" preserveRatio="true">
         <image>
            <Image url="@../../../resources/2560x1440.png" />
         </image>
      </ImageView>
      <HBox alignment="CENTER">
         <children>
            <TilePane alignment="CENTER" hgap="10.0" prefColumns="1" prefHeight="200.0" prefRows="3" prefTileHeight="25.0" prefTileWidth="200.0" prefWidth="200.0" vgap="8.0">
               <HBox.margin>
                  <Insets right="10.0" top="10.0" />
               </HBox.margin>
               <children>
                  <Label text="UserName" />
                  <TextField id="user" fx:id="userField" />
                  <Label text="Password" />
                  <PasswordField id="pass" fx:id="passField" />
                  <Button id="submitBtn" fx:id="subBtn" onAction="#subKey" text="Login" />
               </children>
            </TilePane>
         </children>
      </HBox>
   </children>
</VBox>

Stacktrace for compiler throws java.lang.NullPointerException error on line 101, which is where I try to get the text from PasswordField.

❯  /usr/bin/env /usr/share/OpenJDK_11/jdk-11.0.10+9/bin/java -agentlib:jdwp=transport=dt_socket,server=n,suspend=y,address=localhost:33411 --module-path /home/riley/Downloads/Compressed/toolKits/javafx-sdk-11.0.2/lib --add-modules javafx.controls,javafx.fxml -Dfile.encoding=UTF-8 @/tmp/cp_2txpq641q048qqhdhxcg8rt4u.argfile com.schoolAdmin.app.App
DB Connection ok!
Aug 21, 2021 9:19:45 AM javafx.fxml.FXMLLoader$ValueElement processValue
WARNING: Loading FXML document with JavaFX API of version 16 by JavaFX runtime of version 11.0.2
riley
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
        at javafx.fxml/javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1787)
        at javafx.fxml/javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1670)
        at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
        at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
        at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
        at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
        at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
        at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
        at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
        at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
        at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
        at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
        at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
        at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
        at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
        at javafx.graphics/javafx.scene.Node.fireEvent(Node.java:8879)
        at javafx.controls/javafx.scene.control.Button.fire(Button.java:200)
        at javafx.controls/com.sun.javafx.scene.control.behavior.ButtonBehavior.keyReleased(ButtonBehavior.java:161)
        at javafx.controls/com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274)
        at javafx.base/com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
        at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
        at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
        at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
        at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
        at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
        at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
        at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
        at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
        at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
        at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
        at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
        at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
        at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
        at javafx.graphics/javafx.scene.Scene$KeyHandler.process(Scene.java:4058)
        at javafx.graphics/javafx.scene.Scene$KeyHandler.access$1500(Scene.java:4004)
        at javafx.graphics/javafx.scene.Scene.processKeyEvent(Scene.java:2121)
        at javafx.graphics/javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2595)
        at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:217)
        at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:149)
        at java.base/java.security.AccessController.doPrivileged(Native Method)
        at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$1(GlassViewEventHandler.java:248)
        at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:390)
        at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:247)
        at javafx.graphics/com.sun.glass.ui.View.handleKeyEvent(View.java:547)
        at javafx.graphics/com.sun.glass.ui.View.notifyKey(View.java:971)
        at javafx.graphics/com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
        at javafx.graphics/com.sun.glass.ui.gtk.GtkApplication.lambda$runLoop$11(GtkApplication.java:277)
        at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at com.sun.javafx.reflect.Trampoline.invoke(MethodUtil.java:76)
        at jdk.internal.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at javafx.base/com.sun.javafx.reflect.MethodUtil.invoke(MethodUtil.java:273)
        at javafx.fxml/com.sun.javafx.fxml.MethodHelper.invoke(MethodHelper.java:83)
        at javafx.fxml/javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1782)
        ... 47 more
Caused by: java.lang.NullPointerException
        at com.schoolAdmin.controllers.LoginFXML.subKey(LoginFXML.java:101)
        ... 58 more
Sean Riley
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    Looks like there's no @FXML annotation on the password field – tgdavies Aug 20 '21 at 23:55
  • If you add stacktrace that will help, but based on what you post I am placing my best guess. What I understand is, NPE is coming on this line `passField.getText().toString()` that meant passField.getText() is null. – Anuja Paradkar Aug 21 '21 at 00:51
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    Try making class level property `@FXML private PasswordField passField;` – Anuja Paradkar Aug 21 '21 at 00:59
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    Don’t post links to code. Instead, create a [mre] (a complete example that can be copied and pasted and run to reproduce the issue, and has no more than is required to do that. Typically you do this by creating a new project for that purpose from scratch.) External links to code may go bad, making this useless for future users. – James_D Aug 21 '21 at 02:28
  • Ok might as well do that, thought pasting the whole thing would make it too long – Sean Riley Aug 21 '21 at 07:06
  • @tgdavies does that mean every element has to be annoted by itself, tried grouping variables to be annoted but still didnt work – Sean Riley Aug 21 '21 at 07:31
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    Java field-level annotations apply only to a single field. See https://stackoverflow.com/questions/30210170/is-fxml-needed-for-every-declaration – tgdavies Aug 21 '21 at 07:50
  • @tgdavies I see had done this project before using express and node. Thought of converting it into Java for school project. Let me try declaring items individually. – Sean Riley Aug 21 '21 at 08:06
  • @kleopatra ok will try and get around that even though I called the fxml file in main and it runs. – Sean Riley Aug 21 '21 at 08:08
  • @tgdavies Seems like applying individual annotations worked ``` DB Connection ok! Aug 21, 2021 9:30:17 AM javafx.fxml.FXMLLoader$ValueElement processValue WARNING: Loading FXML document with JavaFX API of version 16 by JavaFX runtime of version 11.0.2 riley SELECT * FROM users WHERE username = 'root' AND password = 'toor' roottoor trueUser Authenticated ``` – Sean Riley Aug 21 '21 at 08:10
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    runs != correct :) – kleopatra Aug 21 '21 at 09:00

0 Answers0