code: @SuppressWarnings(value="unchecked")
  	public Iterator<?> getSessions() {
  		if(!isValid()) {
  			throw new IllegalStateException("SipApplicationSession already invalidated !");
  		}
  		Set<MobicentsSipSession> sipSessions = getSipSessions(false);
  		Set<HttpSession> httpSessions = getHttpSessions();
  		Set protocolSessions = new HashSet();
  		protocolSessions.addAll(httpSessions);
  		protocolSessions.addAll(sipSessions);
  		return protocolSessions.iterator();
  	}
docs: /*
  (non-Javadoc)
  @see javax.servlet.sip.SipApplicationSession#getSessions()