private void txtUbahActionPerformed(java.awt.event.ActionEvent evt) {
        try {
            String sql = "SELECT password FROM t_pengguna WHERE username='" + user + "'";
            java.sql.Connection conn = (Connection) db_connection.configDB();
            java.sql.PreparedStatement pst = conn.prepareStatement(sql);
            rs = pst.executeQuery();
            if (rs.next()) {
                if (!getMD5(txtPassLama.getText()).equals((rs.getString("password")))) {
                    JOptionPane.showMessageDialog(null, "Password lama yang anda masukkan salah!", "Pesan", JOptionPane.WARNING_MESSAGE);
                    txtPassLama.setText("");
                    txtPassLama.requestFocus(true);
                } else if (!txtPassBaru.getText().equals(txtKonfirmasi.getText())) {
                    JOptionPane.showMessageDialog(null, "Password Baru dan Password Konfirmasi Berbeda!", "Pesan", JOptionPane.WARNING_MESSAGE);
                    txtKonfirmasi.setText("");
                    txtKonfirmasi.requestFocus(true);
                } else {
                    String sql2 = "UPDATE t_pengguna SET password = MD5('" + txtPassBaru.getText() + "')";
                    java.sql.PreparedStatement pst2 = conn.prepareStatement(sql2);
                    pst2.executeUpdate();
                    JOptionPane.showMessageDialog(this, "Password Berhasil Diubah !");
                    dispose();
                }
            }
        } catch (Exception e) {
            JOptionPane.showMessageDialog(this, e.getMessage());
        }
    }

    public static String getMD5(String input) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(input.getBytes());

            byte byteData[] = md.digest();

            //convert the byte to hex format method 1
            StringBuffer sb = new StringBuffer();
            for (int i = 0; i < byteData.length; i++) {
                sb.append(Integer.toString((byteData[i] & 0xff) + 0x100,
                        16).substring(1));
            }
            return sb.toString();
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }