code: @Override
      public ServiceReference<?> getServiceReference(String clazz) {
      	Collection<ServiceReference<?>> servrefs = serviceRegistrations.get(clazz);
      	if (servrefs == null || servrefs.size() == 0) {
              return null;
      	}
  
          return servrefs.iterator().next();
      }
docs: Get all {@link ServiceReference} objects matching the fully qualified
  class name given as an argument