What is causing the java.lang.ClassNotFoundException: com.mysql.jdbc.Driver error?

Question

Java

Full text of console output:
Dec. 12, 2020 6:28:40 PM course.UserLogin$2 actionPerformed
SEVERE: null
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581 )
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
at java.base/java. lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:315)
at course.UserLogin$2.actionPerformed(UserLogin.java:113)
at java.desktop/javax.swing .AbstractButton.fireActionPerformed(AbstractButton.java:1967)
at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2308)
at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405
) .setPressed(DefaultButtonModel.java:262)
at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)
at java.desktop/java.awt.Component.processMouseEvent(Component.java:6631 )
at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)
at java.desktop/java.awt.Component.processEvent(Component.java:6396)
at java.desktop/java.awt.Container. processEvent(Container.java:2263)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5007)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)
at java.desktop/java.awt.Component.dispatchEvent (Component.java:4839)
at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4918)
at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4547)
at java.desktop/ java.awt.LightweightDispatcher.dispatchEvent(Container.java:4488)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307)
at java.desktop/java.awt.Window.dispatchEventImpl(Window.java: 2772)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4839)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
at java.desktop/java.awt.EventQueue$4 .run(EventQueue.java:715)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.base /java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
at java.desktop/java.awt.EventQueue$5.run (EventQueue.java:743)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
at java.desktop/java.awt.EventDispatchThread .pumpOneEventForFilters(EventDispatchThread.java:203)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
at java. desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread. java:90)

Source:

package course;

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;

public class UserLogin extends JFrame {

    private static final long serialVersionUID = 1L;
    private JTextField textField;
    private JPasswordField passwordField;
    private JButton btnNewButton;
    private JLabel label;
    private JPanel contentPane;
    private static final String sqlurl = "jdbc:mysql://localhost:3306/mycoursework";
    private static final String sqlname = "root";
    private static final String sqlpassword = "1112"; 
    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    UserLogin frame = new UserLogin();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public UserLogin() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(450, 190, 1014, 597);
        setResizable(false);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JLabel lblNewLabel = new JLabel("Login");
        lblNewLabel.setForeground(Color.BLACK);
        lblNewLabel.setFont(new Font("Times New Roman", Font.PLAIN, 46));
        lblNewLabel.setBounds(423, 13, 273, 93);
        contentPane.add(lblNewLabel);

        textField = new JTextField();
        textField.setFont(new Font("Tahoma", Font.PLAIN, 32));
        textField.setBounds(481, 170, 281, 68);
        contentPane.add(textField);
        textField.setColumns(10);

        passwordField = new JPasswordField();
        passwordField.setFont(new Font("Tahoma", Font.PLAIN, 32));
        passwordField.setBounds(481, 286, 281, 68);
        contentPane.add(passwordField);

        JLabel lblUsername = new JLabel("Username");
        lblUsername.setBackground(Color.BLACK);
        lblUsername.setForeground(Color.BLACK);
        lblUsername.setFont(new Font("Tahoma", Font.PLAIN, 31));
        lblUsername.setBounds(250, 166, 193, 52);
        contentPane.add(lblUsername);

        JLabel lblPassword = new JLabel("Password");
        lblPassword.setForeground(Color.BLACK);
        lblPassword.setBackground(Color.CYAN);
        lblPassword.setFont(new Font("Tahoma", Font.PLAIN, 31));
        lblPassword.setBounds(250, 286, 193, 52);
        contentPane.add(lblPassword);

        btnNewButton = new JButton("Login");
        btnNewButton.setFont(new Font("Tahoma", Font.PLAIN, 26));
        btnNewButton.setBounds(545, 392, 162, 73);
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String userName = textField.getText();
                String password = passwordField.getText();
                try {                  
                    Class.forName("com.mysql.jdbc.Driver");
                    Connection connection = (Connection) DriverManager.getConnection(sqlurl,
                        sqlname, sqlpassword);

                    PreparedStatement st = (PreparedStatement) connection
                        .prepareStatement("Select name, password from user where name=? and password=?");

                    st.setString(1, userName);
                    st.setString(2, password);
                    ResultSet rs = st.executeQuery();
                    if (rs.next()) {
                        dispose();
                        
                        JOptionPane.showMessageDialog(btnNewButton, "You have successfully logged in");
                    } else {
                        JOptionPane.showMessageDialog(btnNewButton, "Wrong Username & Password");
                    }
                } catch (SQLException sqlException) {
                    sqlException.printStackTrace();
                } catch (ClassNotFoundException ex) {
                    Logger.getLogger(UserLogin.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        });

        contentPane.add(btnNewButton);

        label = new JLabel("");
        label.setBounds(0, 0, 1008, 562);
        contentPane.add(label);
    }
}

Answer 1

Hello!
I suspect that the driver is not connected to you. Are you using maven or gradle? If yes, then add the driver according to the documentation.
If you are not using build tools, then make sure the driver is available in the classpath.
Also check if you have mysql installed locally? Otherwise, you are trying to connect to the database on a local computer
jdbc:mysql://localhost:3306/mycoursework
. Also, try replacing this line:
Class.forName("com.mysql.jdbc.Driver");
with
Class.forName(" com.mysql.cj.jdbc.Driver");