byte array in java returning null after conversion from objects

Question

I need to send my phone contacts in android as bytes. So i have crated a bean class implementing serializable , but after converting the arraylist of bean class to byte array, byte array is always showing null. Here is my sample code.

 ByteArrayOutputStream baos = new ByteArrayOutputStream();
 ObjectOutputStream oos = new ObjectOutputStream(baos);
 oos.writeObject(presentContacts);
 byte[] buf = baos.toByteArray();

Here presentContacts is the ArrayList of bean class. Byte array, buf is always returning null but presentContacts is not null.

Answer 1

You should probably close or at least flush the ObjectOutputStream. Something like this

 ByteArrayOutputStream baos = new ByteArrayOutputStream();
 ObjectOutputStream oos = new ObjectOutputStream(baos);
 oos.writeObject(presentContacts);
 oos.flush(); 
 byte[] buf = baos.toByteArray();