Synchronized publisher in Java

import org.zeromq.ZMQ;
import org.zeromq.ZMQ.Context;
import org.zeromq.ZMQ.Socket;

/**
* Synchronized publisher.
*
* Christophe Huntzinger <chuntzin_at_wanadoo.fr>
*/
public class syncpub{
/**
* We wait for 10 subscribers
*/
protected static int SUBSCRIBERS_EXPECTED = 10;

public static void main (String[] args) {
Context context = ZMQ.context(1);

// Socket to talk to clients
Socket publisher = context.socket(ZMQ.PUB);
publisher.bind("tcp://*:5561");

// Socket to receive signals
Socket syncservice = context.socket(ZMQ.REP);
syncservice.bind("tcp://*:5562");

// Get synchronization from subscribers
int subscribers = 0;
while (subscribers < SUBSCRIBERS_EXPECTED) {
// - wait for synchronization request
byte[] value = syncservice.recv(0);

// - send synchronization reply
syncservice.send("".getBytes(), 0);
subscribers++;
}
// Now broadcast exactly 1M updates followed by END
int update_nbr;
for (update_nbr = 0; update_nbr < 1000000; update_nbr++){
publisher.send("Rhubarb".getBytes(), 0);
}

publisher.send("END".getBytes(), 0);

// Give 0MQ/2.0.x time to flush output

try {
Thread.sleep (1);
} catch (InterruptedException e) {
e.printStackTrace();
}

// clean up
publisher.close();
syncservice.close();
context.term();
}
}