code: public Saga continueExisting(final Class<? extends Saga> sagaType, final SagaState state) throws ExecutionException {
          // do not catch exception as in create new
          // if there is an exception during creation, although we want to continue
          // something is terribly wrong -> it has worked at least once before.
          Saga saga = createNewSagaInstance(sagaType);
          saga.setState(state);
          return saga;
      }
docs: Creates a new saga instance attaching an existing saga state.
  @throws ExecutionException Is thrown in case no provider can be found to create an instance.
  The actual cause can be inspected by {@link ExecutionException#getCause()}.