Help me please, what's wrong with my program...

Question

My program has no problem writing data into file. But, I get garbages when my program retrieved data from file. How to solve this, anyone? I tried last 4 days still can't figure out. :(
/* myDate.java */
import java.util.*;
public class myDate extends Object{
private int year;
private int month;
private int day;
public myDate(String newDate) {
StringTokenizer st = new StringTokenizer(newDate, "/");
try {
this.day = Integer.parseInt(st.nextToken());
this.month = Integer.parseInt(st.nextToken());
this.year = Integer.parseInt(st.nextToken());
}catch (NumberFormatException nfe) {
System.out.println("Incorrect Date Format!!!");
System.out.println(nfe.getMessage());
public void setDay (int Day) { this.day = Day; }
public void setMonth (int Month) { this.month = Month; }
public void setYear (int Year) { this.year = Year; }
public String toString() {
return day + "/" + month + "/" + year;
public int getDay() { return day; }
public int getMonth() { return month; }
public int getYear() { return year;  }
/* Inventory.java
* Book Name: 30 bytes Characters
* Book ISBN: 10 bytes Characters
* Book Author: 30 bytes Characters
* Book Genre : 30 bytes Characters
* Book Quantity : 4 bytes integer
* Date of the book purchased : 10 bytes Characters.
import java.io.*;
class Inventory{
private String bookName, bookISBN, bookAuthor, bookGenre;
private int quantity;
private myDate datePurchased;
public Inventory() {
this.bookName = "";
this.bookISBN = "";
this.bookAuthor = "";
this.bookGenre = "";
this.quantity = 0;
this.datePurchased = new myDate("00/00/0000");
public void setBookName(String bookname) {
this.bookName = bookname;
public void setISBN(String BookISBN) {
this.bookISBN = BookISBN;
public void setAuthor(String author) {
this.bookAuthor = author;
public void setGenre(String genre) {
this.bookGenre = genre;
public void setQuantity(int qty) {
this.quantity = qty;
public void setPurchaseDate(String dateOfPurchase) {
this.datePurchased = new myDate(dateOfPurchase);
public String getBookName() { return bookName;}
public String getISBN() { return bookISBN;}
public String getAuthor() { return bookAuthor;}
public String getGenre() { return bookGenre;}
public int getQuantity() { return quantity;}
public String getPurchaseDate() { return datePurchased.toString();}
public String toString() {
return bookName + "\n" + bookISBN + "\n" + bookAuthor + "\n" +
bookGenre + "\n" + quantity + "\n" + datePurchased.toString() +
"\n";
public String fillData(RandomAccessFile raf, int len) throws
IOException {
char data[] = new char[len];
char temp;
for(int i = 0; i < data.length; i++) {
temp = raf.readChar();
data[i] = temp;
return new String(data).replace('\0', ' ');
public void writeStr(RandomAccessFile file, String data, int len)
throws IOException {
StringBuffer buf = null;
if(data != null)
buf = new StringBuffer(data);
else
buf = new StringBuffer(len);
buf.setLength(len);
file.writeChars(buf.toString());
public void writeRecord(RandomAccessFile rafile) throws
IOException {
writeStr(rafile, getBookName(), 30);
writeStr(rafile, getISBN(), 10);
writeStr(rafile, getAuthor(), 30);
writeStr(rafile, getGenre(), 30);
rafile.writeInt(getQuantity());
writeStr(rafile, getPurchaseDate(), 10);
public void readRecord(RandomAccessFile rafile) throws
IOException {
setBookName(fillData(rafile, 30));
setISBN(fillData(rafile, 10));
setAuthor(fillData(rafile, 30));
setGenre(fillData(rafile, 30));
setQuantity(rafile.readInt());
setPurchaseDate(fillData(rafile, 10));
public final static int size() {
return 114;
/* btnPanel.java */
import javax.swing.*;
import java.awt.*;
class btnPanel extends JPanel {
JButton btnSave, btnCancel;
public btnPanel() {
btnSave = new JButton("Save Changes");
btnCancel = new JButton("Cancel");
add(btnSave);
add(btnCancel);
/* inpPanel2.java */
import javax.swing.*;
import java.awt.*;
class inpPanel2 extends JPanel{
JTextField tfBookName, tfBookISBN, tfGenre, tfQuantity,
tfAuthor, tfDatePurchased;
JLabel lblBookName, lblBookISBN, lblAuthor, lblGenre,
lblQuantity, lblDatePurchased;
public inpPanel2() {
tfBookName = new JTextField("",30);
tfBookISBN = new JTextField("",10);
tfGenre = new JTextField("",30);
tfAuthor = new JTextField("",30);
tfQuantity = new JTextField("",10);
tfDatePurchased = new JTextField("",10);
lblBookName = new JLabel("Book Name ");
lblBookISBN = new JLabel("ISBN ");
lblAuthor = new JLabel("Author ");
lblGenre = new JLabel("Genre ");
lblQuantity = new JLabel("Quantity ");
lblDatePurchased = new JLabel("Date Purchased ");
setLayout(new GridLayout(6,2));
add(lblBookName);
add(tfBookName);
add(lblBookISBN);
add(tfBookISBN);
add(lblAuthor);
add(tfAuthor);
add(lblGenre);
add(tfGenre);
add(lblQuantity);
add(tfQuantity);
add(lblDatePurchased);
add(tfDatePurchased);
/* InventoryAdd.java */
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
class InventoryAdd extends JFrame {
btnPanel buttonPanel;
inpPanel2 inputPanel;
Inventory bookInventory;
RandomAccessFile rafile;
public InventoryAdd() {
super("Book Inventory - Add");
buttonPanel = new btnPanel();
buttonPanel.btnSave.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae){
openFile();
bookInventory = new Inventory();
bookInventory.setBookName(inputPanel.tfBookName.getText());
bookInventory.setISBN(inputPanel.tfBookISBN.getText());
bookInventory.setAuthor(inputPanel.tfAuthor.getText());
bookInventory.setGenre(inputPanel.tfGenre.getText());
bookInventory.setQuantity(
Integer.parseInt(
inputPanel.tfQuantity.getText()));
bookInventory.setPurchaseDate(inputPanel.tfDatePurchased.getText());
try {
bookInventory.writeRecord(rafile);
}catch(IOException ioe) {
System.out.println("Cannot Write Record into file...");
System.out.println(ioe.getMessage());
clearInput();
closeFile();
System.out.println(bookInventory.toString());
buttonPanel.btnCancel.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae){
clearInput();
inputPanel = new inpPanel2();
Container c = getContentPane();
c.setLayout(new BorderLayout());
c.add(inputPanel, BorderLayout.CENTER);
c.add(buttonPanel, BorderLayout.SOUTH);
setSize(350, 190);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
public void clearInput() {
inputPanel.tfBookName.setText("");
inputPanel.tfBookISBN.setText("");
inputPanel.tfAuthor.setText("");
inputPanel.tfGenre.setText("");
inputPanel.tfQuantity.setText("");
inputPanel.tfDatePurchased.setText("");
public void openFile() {
try {
rafile = new RandomAccessFile("BOOK_INV.DAT","rw");
rafile.seek(rafile.length());
}catch(IOException ioe) {
System.out.println("Error, Cannot open File");
public void closeFile() {
try{
rafile.close();
}catch(IOException ioe) {
System.out.println("Error, Cannot Close File");
public static void main(String args[]) {
new InventoryAdd();
/* ReadInv.java */
import java.io.*;
class ReadInv {
RandomAccessFile rafile;
Inventory bookInv;
public ReadInv() {
bookInv = new Inventory();
try {
rafile = new RandomAccessFile("BOOK_INV.DAT","r");
rafile.seek(0);
for(int i=0; i < (rafile.length()/bookInv.size()); i++) {
bookInv.readRecord(rafile);
System.out.println(bookInv.toString());
}catch(IOException ioe) {}
public static void main(String args[]) {
new ReadInv();

Answer 1

it's hard to read. please use code tag.
why don't u use object serialization by implements Serializable?
import java.io.Serializable;
public class Inventory implements Serializable {
    // u don't need to change ur code here
}when saving & loading inventory, u can use ObjectOutputStream & ObjectInputStream.
here is an example:
Inventory i = new Inventory();
// set your inventory here
// save to file
ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(
   "InventoryFile.dat")); // file name
out.writeObject(i);
// u can write many object to one single file.
out.close();
// load the file
ObjectInputStream in = new ObjectInputStream(new FileInputStream(
   "InventoryFile.dat"));
Inventory i = (Inventory) in.readObject();