Problem with Fetch Lazy [ Spring Boot ] [ Thymeleaf ]

Question

Well I’m having a problem with my class at the Spring session
Error:

org.hibernate.LazyInitializationException: failed to lazily initialize  

I have a class that represents object in session and is annotated:

@Component
@Scope(value="session", proxyMode= ScopedProxyMode.TARGET_CLASS)
public class Test{
   private Map<Item, Long> items = new LinkedHashMap<>();
   public Colletion<Item> getList() { return items.keySet(); }
   // ...
}

Since it has an Item Linkedhashmap that looks like this :

public class Item {
   private Modelo modelo;
   // Esse metodo retorna uma Soma de Value da Classe Price
   public BigDecimal getPrice() { return modelo.valorSomado(); }
   // ...
}

Which in turn is my Template entity uses JPA spec annotation:

@Entity
public class Modelo extends BaseEntity<Long>{
   @ElementCollection
   private List<Price> prices = new ArrayList<>();
   // ...
}

And within the Price Class contains :

@Embeddable
public class Price {
   @Column(scale=2)
   private BigDecimal value;
   // ...
}

Good when calling the value of the price class in the view, kind of because it’s not @Embeddable(fetch = Fetchtype.EAGER) it can’t load for me by launching that Exception above, but how can I get around it using Hibernate’s LAZY DEFAULT?

VIEW a part where is launching the error:

<tr th:each="item : ${beans.test.list}">        
    <td th:text="${item.modelo.title}" /> <!-- Até aqui funciona -->
    <td class="numeric-cell" th:text="${item.price}"/> <!-- Aqui Lança um erro -->

I have tried to use the Abstractannotationconfigdispatcherservletinitializer using the filter to entityManager always stay open but it did not work very well not for me it persists the error do not know if it may be because I am using Thymeleaf or because I am using this in the wrong way filter used that way but it didn’t work.

public class SpringWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {  
  @Override
  protected Filter[] getServletFilters() {
    return new Filter[]{ 
       new OpenEntityManagerInViewFilter()
    };
  }
  // ...
}

Ah I am using the following tools and frameworks in the Project

• Spring Boot (Security, MVC, DATA, etc)
• Thymeleaf
• Maven

Could someone help me.
Thank you from the start.

Answer 1

Hello as we talked in the comments, a possible solution is to note down your method getList with @Transactional of Spring, because then your method will run inside a transaction avoiding this problem, in code would be something like:

@Component
@Scope(value="session", proxyMode= ScopedProxyMode.TARGET_CLASS)
public class Test{
   private Map<Item, Long> items = new LinkedHashMap<>();

   @Transactional(readOnly = true)
   public Colletion<Item> getList() { return items.keySet(); }
   // ...
}

Note: Some problems may occur if you do not have configuration for use of transactions, if this is the case write in the comments that I teach you how to do.