code: private List<DispatcherTypeProvider> getDispatcherTypeProviders()
     {
        List<DispatcherTypeProvider> result = dispatcherTypeProviders;
        if (result == null) {
           synchronized(this) {
              result = dispatcherTypeProviders;
              if (result == null) {
                 result = Iterators.asList(ServiceLoader.loadTypesafe(DispatcherTypeProvider.class).iterator());
                 Collections.sort(result, new WeightedComparator());
                 dispatcherTypeProviders = result;
              }
           }
        }
        return result;
     }
docs: Returns the list of {@link DispatcherTypeProvider} implementations.