code: public void blockContacts(List<Jid> jids)
              throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
          BlockContactsIQ blockContactIQ = new BlockContactsIQ(jids);
          connection().createStanzaCollectorAndSend(blockContactIQ).nextResultOrThrow();
      }
docs: Block contacts.
  
  @param jids
  @throws NoResponseException
  @throws XMPPErrorException
  @throws NotConnectedException
  @throws InterruptedException