java objectinputstream doubt...

Hi, Im trying to read objects from a file (serialization). I doing this:

ObjectInputStream in = new ObjectInputStream(new FileInputStream("kjh"));
while(in.available() != 0) {
   Object obj = in.readObject();
   // do stuff
}

the file exists, and has objects in it... however it doesn't enter the while cycle... why? while(in.available() != 0) is correct (while there are objects)? Huge thanks