cannot receive over ObjectInputStream... what is going on?

consider this code:

client

DatagramSocket dgs =new DatagramSocket(9999);

byte[] data =newbyte[1024];

DatagramPacket dgp =new DatagramPacket(data, data.length);

dgs.receive(dgp);

Socket sok =new Socket(dgp.getAddress(), 8888);

ObjectOutputStream oos =new ObjectOutputStream(sok.getOutputStream());

oos.writeObject("message from client");

oos.flush();

server

// do a UDP broadcast on port 9999

......

ServerSocket servSok =new ServerSocket(8888);

Socket sok = servSok.accept();

ObjectInputStream ois =new ObjectInputStream(sok.getInputStream());

// .... blocks .... blocks ....

System.out.println("this is never displayed....");

String message = (String) ois.readObject();

what is going on? why does blocking happen

here:

ObjectInputStream ois = new ObjectInputStream(sok.getInputStream());

instead of

String message = (String) ois.readObject();

i've openedObjectInputStreams this way

hundreds of times.

what are some issues for me to investigate?

i don't know how to debug such a fundamental

process.

thanks.

[1664 byte] By [dew2hirooa] at [2007-11-27 5:26:32]