Исключение в потоке "AWT-EventQueue-0" java .lang.NullPointerException вставленные данные не попадают в мой файл sql

Question

Я написал простую программу для подключения моей формы к базе данных, интерфейс работает нормально, но я получаю сообщение об ошибке

Исключение в потоке "AWT-EventQueue-0" java .lang.NullPointerException "для" оператора stmt = con.createStatement (); "

Вот код, который я написал:

package registration_form;

import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;

public class reg extends javax.swing.JFrame {

    Connection con;
    public reg() {
        initComponents();
        createConnection();
    }

    void createConnection() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            java.sql.Connection c =  DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb", "root", "1234");
        }
        catch(ClassNotFoundException | SQLException ex) {
            Logger.getLogger(reg.class.getName()).log(Level.SEVERE, null, ex);
        }
    }


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

        input = new javax.swing.JTextField();
        jButton1 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jButton1.setText("Insert");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(22, 22, 22)
                .addComponent(input, javax.swing.GroupLayout.PREFERRED_SIZE, 230, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(149, 149, 149)
                .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 158, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(141, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(93, 93, 93)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(input, javax.swing.GroupLayout.PREFERRED_SIZE, 84, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 84, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(303, Short.MAX_VALUE))
        );

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

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        try {
            String name = input.getText();
            Statement stmt = con.createStatement();
            String dbop = "INSERT INTO USER VALUES('" + name +"')";
            stmt.execute(dbop);
            stmt.close();
        }
        catch(SQLException ex) {
            Logger.getLogger(reg.class.getName()).log(Level.SEVERE, null, ex);
        }
    }                                        


    public static void main(String args[]) {
        //<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(reg.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(reg.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(reg.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(reg.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new reg().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JTextField input;
    private javax.swing.JButton jButton1;
    // End of variables declaration                   
}