Java Swing JFrame возвращает странный код ошибки

Question

Я пытаюсь запустить проект Java с некоторыми Swing JFrames в качестве интерфейса.

Сборка прошла успешно

Мой метод Main:

public static void main(String[] args) {
    new LoginFrame().setVisible(true);
}

Когда я запускаю проект, рамка открывается на несколько секунд, но это пустое окно (без текстовых полей, меток, кнопок и т. Д. c.), И затем я получаю следующую ошибку: Java возвращено: -1073740771 BUILD FAILED (общее время: 3 секунды).

Я использую Netbeans 8.2 в качестве IDE, а LoginFrame. java выглядит следующим образом:

package view;

import controller.AccountController;
import java.util.List;
import javax.swing.JOptionPane;
import model.Account;


public class LoginFrame extends javax.swing.JFrame {

    private Account foundAccount;

    public LoginFrame() {
        initComponents();
        setLocationRelativeTo(null);
        setVisible(true);
        refresh();
    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        usernameField = new javax.swing.JTextField();
        jLabel1 = new javax.swing.JLabel();
        passwordField = new javax.swing.JTextField();
        jLabel2 = new javax.swing.JLabel();
        loginButton = new javax.swing.JButton();
        registerButton = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jLabel1.setText("username:");

        jLabel2.setText("parola:");

        loginButton.setText("Login");
        loginButton.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                loginButtonMouseClicked(evt);
            }
        });

        registerButton.setText("Inregistrare");
        registerButton.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                registerButtonMouseClicked(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jLabel1)
                    .addComponent(jLabel2))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                    .addComponent(passwordField, javax.swing.GroupLayout.DEFAULT_SIZE, 179, Short.MAX_VALUE)
                    .addComponent(usernameField))
                .addGap(142, 142, 142))
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(199, 199, 199)
                        .addComponent(loginButton))
                    .addGroup(layout.createSequentialGroup()
                        .addGap(183, 183, 183)
                        .addComponent(registerButton)))
                .addContainerGap(188, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(76, 76, 76)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(usernameField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jLabel1))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(passwordField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jLabel2))
                .addGap(18, 18, 18)
                .addComponent(loginButton)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(registerButton)
                .addContainerGap(89, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        

    private void loginButtonMouseClicked(java.awt.event.MouseEvent evt) {                                         
        String username = usernameField.getText();
        String password = usernameField.getText();
        List<Account> accounts = AccountController.getInstance().getAllAccounts();

        boolean accountExists = false;
        for (Account account : accounts){
            if(account.getUsername() == username && account.getPassword() == password){
                accountExists = true;
                foundAccount = AccountController.getInstance().getAccountByIndex(account.getId());
                break;
            }
        }

        if(accountExists){
            new MainFrame(foundAccount);
        }else{
            JOptionPane.showMessageDialog(this, "Username-ul sau parola nu sunt bine introduse!");
            refresh();
        }
    }                                        

    private void refresh(){
        usernameField.setText("");
        passwordField.setText("");
    }

    private void registerButtonMouseClicked(java.awt.event.MouseEvent evt) {                                            
        new RegisterFrame();
    }                                           



    // Variables declaration - do not modify                     
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JButton loginButton;
    private javax.swing.JTextField passwordField;
    private javax.swing.JButton registerButton;
    private javax.swing.JTextField usernameField;
    // End of variables declaration                   
}

Пожалуйста, объясните мне, что именно я делаю неправильно.

Спасибо!