public ServiceModule(String address, int port, int maxRef) {
        address_ = address;
        port_ = port;
        try {
            // hack to get the exception at initialization time
            Host host = new PGridHost(address_, port_);
        } catch (UnknownHostException e) {
            throw new IllegalArgumentException(e.getCause());
        }
        maxRef_ = maxRef;
    }