Parsing a date error.help with small program

import java.io.*;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;
public class Book {


    String isbn;
    int copyNumber;
    String title;
    String author;
    int statistics;
    Date borrowDate = new Date();
    Date returnDate = new Date();
    int libraryCardNumber;
    DateFormat formatter = new SimpleDateFormat("yy/mm/dd");

public Book(String newIsbn, int newCopyNumber, String newTitle, String newAuthor,
        int newStatistics, Date newBorrowDate, Date newReturnDate, int newLibraryCardNumber)
{
    isbn = newIsbn;
    copyNumber = newCopyNumber;
    title = newTitle;
    author = newAuthor;
    statistics = newStatistics;
    borrowDate = newBorrowDate;
    returnDate = newReturnDate;
    libraryCardNumber = newLibraryCardNumber;
}

public Book(){

}

public Book(String newRow) throws ParseException
{
    String[] token = newRow.split("#");
    
                isbn = token[0];
                copyNumber = Integer.parseInt(token[1]);
                title = token[2];
                author = token[3];
                statistics = Integer.parseInt(token[4]);
                borrowDate = (Date)formatter.parse(token[5]);
                returnDate = (Date)formatter.parse(token[6]);
                libraryCardNumber = Integer.parseInt(token[7]);
}

public String getIsbn()
    {
     return isbn;
    }

public void setIsbn(String isbn)
    {
    this.isbn = isbn;
    }

public int getCopyNumber()
{
    return copyNumber;
}

public void setCopyNumber(int copyNumber)
{
    this.copyNumber = copyNumber;
}

public String getTitle()
{
    return title;
}

private void setTitle(String title)
{
    this.title = title;
}

public String getAuthor()
{
    return author;
}

private void setAuthor(String author)
{
    this.author = author;
}

public int getStatistics()
{
    return statistics;
}

public void setStatistics(int statistics)
{
    this.statistics = statistics;
}

public Date setBorrowDate()
{
    return borrowDate;
}

public void getBorrowDate(Date borrowDate)
{
    this.borrowDate = borrowDate;
}

public Date getReturnDate()
{
    return returnDate;
}

public void setReturnDate (Date returnDate)
{
    this.returnDate = returnDate;
}

public int getLibraryCardNumber()
{
    return libraryCardNumber;
}

public void setLibraryNumber(int libraryCardNumber)
{
    this.libraryCardNumber = libraryCardNumber;
}


}

import java.io.*;
import java.text.ParseException;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.swing.JFileChooser;


public class WriteFromBookFile {

    private static Pattern pattern;

    public static void main(String[] args) throws FileNotFoundException, ParseException, IOException {

        JFileChooser fileChooser = new JFileChooser();
        if(fileChooser.showOpenDialog(null)
                == JFileChooser.APPROVE_OPTION){
        ArrayList<Book> newBooks = new ArrayList<Book>();
        ArrayList<Book> errorBooks = new ArrayList<Book>();


        java.io.File file = fileChooser.getSelectedFile();
    //  try{  BufferedReader reader = new BufferedReader(new FileReader("books.txt"));
       Scanner input = new Scanner(file);
       String line = input.nextLine();
        while (line != null) {


            Book newBook = new Book(line);

            String[] newToken = line.split("#");

            pattern = Pattern.compile("ISBN\\x20(?=.{13}$)\\d{1,5}([- ])\\d{1,7}\\1\\d{1,6}\\1(\\d|X)$");
            Matcher matchIsbn = pattern.matcher(newToken[0]);
            pattern = Pattern.compile("[\\d]+");
            Matcher matchCopyNumber = pattern.matcher(newToken[1]);
            pattern = Pattern.compile("[\\D&&\\w]+");
            Matcher matchTitle = pattern.matcher(newToken[2]);
            pattern = Pattern.compile("[\\D&&\\w]+");
            Matcher matchAuthor = pattern.matcher(newToken[3]);
            pattern = Pattern.compile("[\\d]+");
            Matcher matchStatistics = pattern.matcher(newToken[4]);
            pattern = Pattern.compile("YY/MM/DD");
            Matcher matchBorrowDate = pattern.matcher(newToken[5]);
            pattern = Pattern.compile("YY/MM/DD");
            Matcher matchReturnDate = pattern.matcher(newToken[6]);
            pattern = Pattern.compile("[\\d]+");
            Matcher matchLibraryCardNumber = pattern.matcher(newToken[7]);

            /*  if(matchIsbn.matches(newBook.getIsbn()) && matchCopyNumber.matches(newBook.getCopyNumber())
            && matchTitle.matches(newBook.getTitle()) && matchAuthor.matches(newBook.getAuthor())
            && matchStatistics.matches(newBook.getStatistics()) && matchBorrowDate.matches(newBook.getBorrowDate())
            && matchReturnDate.matches(newBook.getReturnDate()) && matchLibraryCardNumber.matches(newBook.getLibraryCardNumber()));*/
            if (matchIsbn.matches() && matchCopyNumber.matches() && matchTitle.matches() && matchAuthor.matches()
                    && matchStatistics.matches() && matchBorrowDate.matches() && matchReturnDate.matches() && matchLibraryCardNumber.matches())

            {
                newBooks.add(newBook);
            }
                   else
                errorBooks.add(newBook);
            

line = input.nextLine();
    }
input.close();

       java.io.File newBookFile = new java.io.File("newBook.txt");

    if(newBookFile.exists()){
        System.out.println("File exists.");
        System.exit(0);
    }

    java.io.PrintWriter output = new java.io.PrintWriter(newBookFile);

    for(int i = 0; i < newBooks.size(); i++)
    {
        output.print(newBooks.get(i));
    }
        output.close();
    }
}
}