code: private DefaultSipApplicationRouterInfo getFirstRequestApplicationEntry(
              List<? extends SipApplicationRouterInfo> defaultSipApplicationRouterInfoList, SipServletRequest initialRequest) {
          SipSession sipSession = initialRequest.getSession(false);
          if (sipSession != null) {
              String appName = sipSession.getApplicationSession().getApplicationName();
              Iterator<? extends SipApplicationRouterInfo> iterator = defaultSipApplicationRouterInfoList.iterator();
              while (iterator.hasNext()) {
                  DefaultSipApplicationRouterInfo next = (DefaultSipApplicationRouterInfo) iterator.next();
                  if (next.getApplicationName().equals(appName))
                      return next;
              }
          }
          return null;
      }
docs: /*
  This method is checking if the application that initiated the request is currently configured to be called for this
  method. Apps that initiate request may not be in the list.