code: protected void processStanza(final Stanza stanza) throws InterruptedException {
          assert (stanza != null);
  
          final SmackDebugger debugger = this.debugger;
          if (debugger != null) {
              debugger.onIncomingStreamElement(stanza);
          }
  
          lastStanzaReceived = System.currentTimeMillis();
          // Deliver the incoming packet to listeners.
          invokeStanzaCollectorsAndNotifyRecvListeners(stanza);
      }
docs: Processes a stanza after it's been fully parsed by looping through the installed
  stanza collectors and listeners and letting them examine the stanza to see if
  they are a match with the filter.
  
  @param stanza the stanza to process.
  @throws InterruptedException