Exception in thread "AWT-eventqueue-0" java.lang.nullpointerexception

Question

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Java

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author hifi
 */
public class LoginForm extends javax.swing.JFrame {

    /**
     * Creates new form LoginForm
     */
    public LoginForm() {
        initComponents();
     lbl_U.setVisible(false);
     lbl_p.setVisible(false);
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jTextField_Username = new javax.swing.JTextField();
        jPasswordField1 = new javax.swing.JPasswordField();
        jButton_Cancel = new javax.swing.JButton();
        jButton_Login2 = new javax.swing.JButton();
        jLabel4 = new javax.swing.JLabel();
        jLabel5 = new javax.swing.JLabel();
        lbl_U = new javax.swing.JLabel();
        lbl_p = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setLocation(new java.awt.Point(0, 0));
        setLocationByPlatform(true);

        jPanel1.setBackground(new java.awt.Color(204, 255, 204));

        jLabel1.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N
        jLabel1.setText("Login Form");

        jLabel2.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        jLabel2.setText("Password:");

        jLabel3.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        jLabel3.setText("Username:");

        jTextField_Username.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N

        jPasswordField1.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N

        jButton_Cancel.setFont(new java.awt.Font("Tahoma", 1, 12)); // NOI18N
        jButton_Cancel.setIcon(new javax.swing.ImageIcon(getClass().getResource("/images/delete.png"))); // NOI18N
        jButton_Cancel.setText("Cancel");

        jButton_Login2.setFont(new java.awt.Font("Tahoma", 1, 12)); // NOI18N
        jButton_Login2.setIcon(new javax.swing.ImageIcon(getClass().getResource("/images/login.png"))); // NOI18N
        jButton_Login2.setText("LogIn");
        jButton_Login2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton_Login2ActionPerformed(evt);
            }
        });

        jLabel4.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N

        jLabel5.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N

        lbl_U.setBackground(new java.awt.Color(255, 0, 0));
        lbl_U.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        lbl_U.setForeground(new java.awt.Color(255, 51, 0));
        lbl_U.setText("*");

        lbl_p.setBackground(new java.awt.Color(255, 0, 0));
        lbl_p.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
        lbl_p.setForeground(new java.awt.Color(255, 0, 51));
        lbl_p.setText("*");

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(100, 100, 100)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jLabel4)
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addComponent(jButton_Cancel)
                        .addGap(18, 18, 18)
                        .addComponent(jButton_Login2)))
                .addGap(0, 78, Short.MAX_VALUE))
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(40, 40, 40)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jLabel2)
                    .addComponent(jLabel3))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                        .addGap(0, 0, Short.MAX_VALUE)
                        .addComponent(jLabel5))
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                            .addGroup(jPanel1Layout.createSequentialGroup()
                                .addComponent(jTextField_Username, javax.swing.GroupLayout.PREFERRED_SIZE, 170, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                .addComponent(lbl_U, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                            .addGroup(jPanel1Layout.createSequentialGroup()
                                .addComponent(jPasswordField1, javax.swing.GroupLayout.PREFERRED_SIZE, 170, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                .addComponent(lbl_p, javax.swing.GroupLayout.PREFERRED_SIZE, 9, javax.swing.GroupLayout.PREFERRED_SIZE)))
                        .addGap(0, 0, Short.MAX_VALUE))))
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(jLabel1)
                .addGap(119, 119, 119))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(43, 43, 43)
                .addComponent(jLabel1)
                .addGap(42, 42, 42)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel5)
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addComponent(jLabel4)
                        .addGap(11, 11, 11)
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jTextField_Username, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(jLabel3)
                            .addComponent(lbl_U))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                                .addComponent(jPasswordField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addComponent(lbl_p))
                            .addComponent(jLabel2))
                        .addGap(42, 42, 42)
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jButton_Login2, javax.swing.GroupLayout.PREFERRED_SIZE, 34, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(jButton_Cancel, javax.swing.GroupLayout.PREFERRED_SIZE, 34, javax.swing.GroupLayout.PREFERRED_SIZE))))
                .addContainerGap(67, Short.MAX_VALUE))
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );

        pack();
    }//                         

    private void jButton_Login2ActionPerformed(java.awt.event.ActionEvent evt) {                                               
       lbl_U.setVisible(false);
       lbl_p.setVisible(false);
        if (jTextField_Username.getText().equals(""))
        {
            lbl_U.setVisible(true);
        }
        if(String.valueOf(jPasswordField1.getPassword()).equals(""))
        {
            lbl_p.setVisible(true);
        }
        else
        {
            Connection con = MyConnection.getConnection();
            PreparedStatement ps;
            
           try {
               ps = con.prepareStatement("SELECT * FROM user WHERE username = ? AND password = ?");
               ps.setString(1, jTextField_Username.getText());
               ps.setString(2, String.valueOf(jPasswordField1.getPassword()));
               
               ResultSet rs = ps.executeQuery();
               
               if(rs.next())
               {
                   System.out.println("YES");
               }
               else
               {
                   System.out.println("NO");
               }
               
               
           } catch (SQLException ex) {
               Logger.getLogger(LoginForm.class.getName()).log(Level.SEVERE, null, ex);
           }
        }
    }                                              

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(LoginForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(LoginForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(LoginForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(LoginForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new LoginForm().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton_Cancel;
    private javax.swing.JButton jButton_Login2;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JLabel jLabel5;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPasswordField jPasswordField1;
    private javax.swing.JTextField jTextField_Username;
    private javax.swing.JLabel lbl_U;
    private javax.swing.JLabel lbl_p;
    // End of variables declaration                   
}

What I have tried:

Java

run:
com.mysql.jdbc.Driver
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at LoginForm.jButton_Login2ActionPerformed(LoginForm.java:196)
	at LoginForm.access$000(LoginForm.java:19)
	at LoginForm$1.actionPerformed(LoginForm.java:80)
	at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
	at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
	at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
	at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
	at java.awt.Component.processMouseEvent(Component.java:6533)
	at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
	at java.awt.Component.processEvent(Component.java:6298)
	at java.awt.Container.processEvent(Container.java:2238)
	at java.awt.Component.dispatchEventImpl(Component.java:4889)
	at java.awt.Container.dispatchEventImpl(Container.java:2296)
	at java.awt.Component.dispatchEvent(Component.java:4711)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4897)
	at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4534)
	at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4475)
	at java.awt.Container.dispatchEventImpl(Container.java:2282)
	at java.awt.Window.dispatchEventImpl(Window.java:2746)
	at java.awt.Component.dispatchEvent(Component.java:4711)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760)
	at java.awt.EventQueue.access$500(EventQueue.java:97)
	at java.awt.EventQueue$3.run(EventQueue.java:709)
	at java.awt.EventQueue$3.run(EventQueue.java:703)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
	at java.awt.EventQueue$4.run(EventQueue.java:733)
	at java.awt.EventQueue$4.run(EventQueue.java:731)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
BUILD SUCCESSFUL (total time: 36 seconds)

Posted 3-Oct-18 8:04am

Member 14006581

Updated 4-Oct-18 17:13pm

wseng

v2

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Comments

Richard Deeming 3-Oct-18 15:38pm

An unformatted code-dump with no explanation is not a question!

wseng 4-Oct-18 23:08pm

Please learn how to ask a question

1 solution

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vcbeaut · Answer 1 · 2018-10-04T17:13:00

Solution 1

you can locate the line where is exception

Posted 4-Oct-18 17:13pm

vcbeaut

Comments

Richard Deeming 5-Oct-18 7:36am

If you want to ask for clarification, click the "Have a Question or Comment?" button under the question. DO NOT post your comment as a "solution" to the question.