public class Util {

     public String path = "c:/book.db";

     public  ArrayList<Book> readBook() {

         ArrayList<Book> s = new ArrayList<Book>();

         try {

             FileInputStream fis = new FileInputStream(path);

             ObjectInputStream ois = new ObjectInputStream(fis);

             s = (ArrayList<Book>)ois.readObject();

             fis.close();

             ois.close();

         } catch (Exception e) {

         }

         return s;

     }

     public void writeBook(Book book) {

         ArrayList<Book> books = readBook();

         books.add(book);

         try {

             FileOutputStream fos = new FileOutputStream(path);

             ObjectOutputStream oos = new ObjectOutputStream(fos);

             oos.writeObject(books);

             fos.close();

             oos.close();

         } catch (Exception e) {

         }

     }

 }