code: public void unsubscribe(String jid) throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
          unsubscribe(jid, null);
      }
docs: Remove the subscription related to the specified JID.  This will only
  work if there is only 1 subscription.  If there are multiple subscriptions,
  use {@link #unsubscribe(String, String)}.
  
  @param jid The JID used to subscribe to the node
  @throws XMPPErrorException
  @throws NoResponseException
  @throws NotConnectedException
  @throws InterruptedException