throws ParameterNotInstantiableException,
          IllegalAccessException,
          InvocationTargetException,
          FactoryMethodReturnsNullException {
    if (cls.isEnum()) {
      T[] constants = cls.getEnumConstants();
      if (constants != null && constants.length > 0) {
        return constants[0];
      } else {
        return null;
      }
    }
    TypeToken<T> type = TypeToken.of(cls);

   */
  @VisibleForTesting
  static <E extends Enum<E>> Map<E, LockGraphNode> createNodes(Class<E> clazz) {
    EnumMap<E, LockGraphNode> map = Maps.newEnumMap(clazz);
    E[] keys = clazz.getEnumConstants();
    int numKeys = keys.length;
    ArrayList<LockGraphNode> nodes = Lists.newArrayListWithCapacity(numKeys);
    // Create a LockGraphNode for each enum value.
    for (E key : keys) {