Cannot get stored document from mongodb using spring data

I have document with "_id" : ObjectId("5449567cdf97f277c50d1ce2") but I am getting null when trying to get it by id using findOne. How to solve it?

main

public class MongoDBJDBC {
    public static void main( String args[] ){
        ConfigurableApplicationContext context = new ClassPathXmlApplicationContext("spring/applicationContext.xml");

        ProductService productService = context.getBean(ProductService.class);
        Product product = productService.get("5449567cdf97f277c50d1ce2"); // null here
        }
}

service

@Service
public class ProductService {
    @Autowired
    private ProductDao productDao;
    @Autowired
    private ProductPropertiesDao productPropertiesDao;

    public void add(Product product) {
        productDao.save(product);
    }

    public void update(Product product) {
        productDao.save(product);
    }

    public Product get(String id) {
        return productDao.get(id);
    }

dao

    @Repository
    public class ProductDao  {

        @Autowired
        private MongoOperations mongoOperations;
 public Product get(String id) {
        return mongoOperations.findOne(Query.query(Criteria.where("id").is(new ObjectId(id))), Product.class);
    }
}

entity

@Document(collection = Product.COLLECTION_NAME)
public class Product implements Serializable {

    public Product() {
    }

    public static final String COLLECTION_NAME = "product";

    @Id
    private String _id;
    private String name;
   }

document

{
    "_id" : ObjectId("5449567cdf97f277c50d1ce2"),
    "name" : "product"
}