code: private void loadHealthyServices() {
  
          try {
              String serviceName = doneQueue.poll();
  
              while (serviceName != null) {
  
                  final String serviceNameToFetch = serviceName;
  
                  /* Don't load the service if it is already being loaded. */
                  if (!serviceNamesBeingLoaded.contains(serviceNameToFetch)) {
                      serviceNamesBeingLoaded.add(serviceNameToFetch);
                      executorService.submit(() -> {
                       /*
                         Loading a service pool might take a while so
                         the actual load operation happens in its own thread.
                        */
                          doLoadHealthServices(serviceNameToFetch);
                      });
                  }
                  serviceName = doneQueue.poll();
              }
          } catch (Exception ex) {
              ex.printStackTrace();
          }
      }
docs: Iterate through the health service queue and load the services.