rx.initCause(exc);
rx.detail = exc;
  protected void activate() throws RemoteException  {    try      {        Remote self = actId.activate(false);                // This will call UnicastServer.exportObject, replacing null by        // the activated object (self) in the object map.        exportObject(self);      }    catch (RemoteException rex)      {        throw rex;      }    catch (Exception exc)      {        RemoteException rx = new RemoteException("Activation failed.");        rx.initCause(exc);        throw rx;      }  }