Cannot create typedquery for query with more than one return using requested result type

When you encounter the error message “cannot create typedquery for query with more than one return using requested result type”, it means that you are trying to create a TypedQuery object in JPA with a result type that does not match the expected return type of the query.

Let’s dive into more details and see an example to better understand this error:

// Assume we have an entity class called "Product"
@Entity
public class Product {
    // ...
}

// In your repository or service class
@Repository
public class ProductRepository {
    // ...

    public List<Product> findByCategory(String category) {
        EntityManager em = entityManagerFactory.createEntityManager();
        CriteriaBuilder cb = em.getCriteriaBuilder();
        CriteriaQuery<Product> cq = cb.createQuery(Product.class);
        Root<Product> root = cq.from(Product.class);
        cq.select(root).where(cb.equal(root.get("category"), category));
        TypedQuery<String> query = em.createQuery(cq); // ERROR: Mismatch in return type
        // ...
    }
}

In the above example, we are trying to create a TypedQuery with the result type as String instead of the expected return type Product. This will result in the mentioned error message. To fix it, we need to provide the correct return type Product while creating the TypedQuery:

TypedQuery<Product> query = em.createQuery(cq); // Corrected typed query

By specifying the correct return type, we resolve the error and ensure that the query result is properly mapped to the expected type.