if (impl == null) throw new SocketException ("Not connected");
if (isClosed()) throw new SocketException("ServerSocket is closed");
  public int getReceiveBufferSize ()    throws SocketException  {    if (impl == null)      throw new SocketException ("Not connected");    Object buf = impl.getOption (SocketOptions.SO_RCVBUF);    if (!(buf instanceof Integer))      throw new SocketException ("Internal Error: Unexpected type");        return ((Integer) buf).intValue ();  }