LazyInitializationException with @Any(fetch = FetchType.EAGER) and Spring-boot

Question

I got a common exception " org.hibernate.LazyInitializationException: could not initialize proxy - no Session " in spite of " fetch = FetchType.EAGER " and I can't (wan't) manage hibernate session manually (I use Spring-Boot-starter-data-jpa).

I have a Hilder entity, that contains property of CommonType (TapeA or TypeB):

  @Entity
public class Holder<T extends CommonType> {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private long id;

@Any(metaColumn = @Column(name = "type", nullable = false), optional = false, fetch = FetchType.EAGER)
@Cascade(org.hibernate.annotations.CascadeType.ALL )
@AnyMetaDef(
        idType = "long",
        metaType = "string",
        metaValues = {
                @MetaValue(value = "TypeA", targetEntity = TypeB.class),
                @MetaValue(value = "TypeB", targetEntity = TypeA.class)
        })
@JoinColumn(name = "property_id", nullable = false)
private T type; 
 //getters and setters}

TypeB looks like TypeA:

@Entity
public class TypeA implements CommonType {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;

    private double param=0;
//getters and setters
}

And repository for Holder :

import org.springframework.transaction.annotation.Transactional;

@Transactional
public interface HolderRepository extends CrudRepository<Holder, Long> {
}

Runner:

@Configuration
@EnableAutoConfiguration
public class Application {

    public static void main(String[] args) {
        ConfigurableApplicationContext context =       SpringApplication.run(Application.class);
    HolderRepository repository = context.getBean(HolderRepository.class);

    TypeA simpleDeviceState = new TypeA();
    Holder<TypeA> holder = new Holder<>(simpleDeviceState);
    repository.save(holder);

    Holder holder1=repository.findAll().iterator().next();
    TypeA typeA= (TypeA) holder1.getType();

    System.out.println("Param: "+typeA.getParam());
    context.close();
}}

Pom contain org.springframework.boot::spring-boot-starter-data-jpa and com.h2database::h2 only.

In printing point exception appears. I guess that I get org.hibernate.LazyInitializationException because fetch = FetchType.EAGER does't work.

Also cascading works for PERSIST only. Maybe the problem in mixing Hibernate and JPA, but I can not handle it. Thanks in advance!

Answer 1

It is not the good solution, but it works. But I would like to get better one. It is service with @Transactional and Hibernate.initialize:

@Component
@Transactional
public class ServiceHolder {

@Autowired
HolderRepository holderRepository;

public Holder getH(long id) {
    Holder holder = holderRepository.findOne(id);
    Hibernate.initialize(holder.getType());
    return holder;
}

}