docs: @Reference(service = Application.class,
                 cardinality = ReferenceCardinality.MULTIPLE,
                 policy = ReferencePolicy.DYNAMIC,
                 target = "(application.state=STARTING)")
      protected void addStartingApplication(ServiceReference<Application> ref) {
          String appName = (String) ref.getProperty(NAME);
          lock.writeLock().lock();
          try {
              if (!appStates.containsKey(appName))
                  appStates.put(appName, ApplicationState.STARTING);
          } finally {
              lock.writeLock().unlock();
          }
      }