On a Win32 machine, a socket with InetAddress as a broadcast address cannot be opened. By broadcast address, I mean one of type say "129.144.251.255", i.e. a subnet broadcast with all bits reserved for host addresses set to 1.
This was tested simply using DatagramSocket(port, InetAddress) with above address when machine was on the 251 subnet.
The same test works fine on Solaris. The creation of the socket results in an exception.
The exception received is java.net.BindException with message
Test program:

import java.net.*;
import java.lang.*;


public class test {
    DatagramSocket sock = null;
    InetAddress addr;
    public static void main(String[] args){
        new test();
    }
    
    public test(){
        try{
            addr = InetAddress.getByName("129.144.251.255");
                System.err.println("address is " + addr.toString());
            sock = new DatagramSocket(49152, addr);
            System.out.println("sock is " + sock);
        }catch (Exception e){
            System.err.println("exception " + e.getMessage() + e );
        }
    }
}

"Cannot assign requested address".