code: public static <T> Collection<T> getLoadedImplementations(Class<T> clazz)
    {
      @SuppressWarnings("unchecked")
      Collection<T> retVal = (Collection<T>) extensionsMap.get(clazz);
      if (retVal == null) {
        return new HashSet<>();
      }
      return retVal;
    }
docs: @param clazz service class
  @param <T>   the service type
  
  @return Returns a collection of implementations loaded.