Error while reading objects from a file

Question

Below is a short code to explain the problem i am facing
i have been working on the same for past one week i am facing exceptions while reading a file containing more than one objects
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.logging.Level;
import java.util.logging.Logger;
* @author sakshi
public class Storingobject implements Serializable{
    int x,y;
    public void addObject()
        //Storingobject temp;
        ObjectOutputStream objOut=null;
        try {
            objOut = new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream("temp.dat")));//if i pass true as parameter in FileOutputStream it gives Stream Corrupted exception
        } catch (IOException ex) {
            Logger.getLogger(Storingobject.class.getName()).log(Level.SEVERE, null, ex);
        try {
            // while((temp=objOut.writeObject(o))!=null)
            objOut.writeObject(this);
            System.out.println("Saved..");
            objOut.close();
        } catch (IOException ex) {
            Logger.getLogger(Storingobject.class.getName()).log(Level.SEVERE, null, ex);
    public void readobject()
        int i=1;
        Storingobject temp;
        ObjectInputStream objIn=null;
        try {
            objIn = new ObjectInputStream(new BufferedInputStream(new FileInputStream("temp.dat")));
        } catch (IOException ex) {
            Logger.getLogger(Storingobject.class.getName()).log(Level.SEVERE, null, ex);
        try {
            while ((temp = (Storingobject) objIn.readObject()) != null) {
                System.out.println("VAlues of object i++ :");
                System.out.println("X: "+temp.x+"Y: "+temp.y);
        } catch (IOException ex) {
            Logger.getLogger(Storingobject.class.getName()).log(Level.SEVERE, null, ex);
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(Storingobject.class.getName()).log(Level.SEVERE, null, ex);
    public static void main(String args[])
        Storingobject o1=new Storingobject();
        o1.x=10;o1.y=15;
        o1.addObject();
        o1.readobject();
}

Answer 1

//if i pass true as parameter in FileOutputStream it gives Stream Corrupted exceptionI agree. You can't append to a file written with an ObjectOutputStream. You would have to read it all in, write it all out again and write the new object. You're better off keeping the file open while you still have objects to write to it.
while ((temp = (Storingobject) objIn.readObject()) != null) {ObjectInputStream.readObject() only returns null if you wrote a null. If you're not writing nulls, the correct technique is to loop until you get an EOFException. I don't favour explicitly writing a null just to get around this as suggested above, as it means you can never write a null for any other purpose.