Executing multiple prepared mysql statements in Java (Android Studio)

Question

I want to know if this is the correct way of executing multiple MySQL prepared statements in Android Studio.

I have created two tables in a database, namely t1 and t2. I want to be able to update both tables when the user presses a button. When the user presses the button the following code is executed:

new Post_data_Delete(Picking.this, order_var, Client_Name,scanned_tag, new_cylinder_amount, quan_type).execute();

The code is the Async task that runs when the button is pressed. The code works, but is this the correct way of doing this?

private static class Post_data_Delete extends AsyncTask<Void, Void, Void> {
    private final WeakReference<Picking> activityWeakReference;

    String records = "";
    String error = "";
    String Order_number;
    String Name_of_client;
    String data;
    String New_quanity;
    Integer Quanity_type;

    private Post_data_Delete(Picking activity,String order, String client, String scanned_data, Integer quanity, Integer quanity_type) {
        activityWeakReference = new WeakReference<Picking>(activity);

        Order_number = order;
        Name_of_client = client;
        data = scanned_data;
        New_quanity = quanity.toString();
        Quanity_type = quanity_type;

    }

    @RequiresApi(api = Build.VERSION_CODES.N)
    @Override
    protected Void doInBackground(Void... voids) {

        try
        {
            Class.forName("com.mysql.jdbc.Driver");
            Connection c = DriverManager.getConnection("jdbc:mysql://10.168.09.66:3306/db", "u", "p");

            PreparedStatement update_cylinder = c.prepareStatement("UPDATE `db`.`t1` SET `IN` = ?, `CLIENT` = ? WHERE (`TAG` = ?)");
            update_cylinder.setString(1,"OUT");
            update_cylinder.setString(2,Name_of_client);
            update_cylinder.setString(3,data);
            update_cylinder.execute();
            update_cylinder.close();

            if(Quanity_type == 1)
            {
                PreparedStatement st = c.prepareStatement("UPDATE `db`.`t2` SET `QUANITY` = ? WHERE (`ORDER` = ?)");

                st.setString(1,New_quanity);
                st.setString(2, Order_number);
                st.execute();
                st.close();
            }

            else if(Quanity_type == 2)
            {
                PreparedStatement st = c.prepareStatement("UPDATE `db`.`t2` SET `QUANITY` = ? WHERE (`ORDER` = ?)");

                st.setString(1,New_quanity);
                st.setString(2, Order_number);
                st.execute();
                st.close();
            }

            else {}

            c.close();
        }

        catch(Exception e)
        {
            error = e.toString();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void aVoid) {
        super.onPostExecute(aVoid);

        Picking activity = activityWeakReference.get();
        if(activity == null || activity.isFinishing()) {
            return;
        }

        if(error != "") {
            Toast.makeText(activity, error, Toast.LENGTH_SHORT).show();
        }

        else{
            Toast.makeText(activity, "Successfully entered into database", Toast.LENGTH_LONG).show();
        
        }
    }

}