Send Object from Service to Activity (Can't marshal non-Parcelable)

I'm trying to send data from my activity to a service and receive some information back, but i'm getting:

java.lang.RuntimeException: Can't marshal non-Parcelable objects across processes.

The code from activity looks like this:

Message msg = Message.obtain(null, 1);
    msg.obj=1;
    msg.replyTo=new Messenger(new PlanRequestIncomingHandler());
    try {
        msgService.send(msg);
    } catch (RemoteException e) {
        Log.i(tag, "Can not send msg to service");
        e.printStackTrace();
    }

When I set msg.obj = something I get java.lang.RuntimeException, can somebody help me?