code: public <E> E load(Class<E> entityClass, long id) {
      return load(entityClass, null, id);
    }
docs: Loads and returns the entity with the given ID. The entity is assumed to be a root entity (no
  parent). The entity kind is determined from the supplied class.
  
  @param entityClass
  the entity class
  @param id
  the ID of the entity
  @return the Entity object or <code>null</code>, if the the entity with the given ID does not
  exist in the Cloud Datastore.
  @throws EntityManagerException
  if any error occurs while inserting.