Failed to execute CommandLineRunner - Hibernate LazyInitializationException

Question

I'm developing a Java application using Spring Boot and JPA (Java Persistence API) with Hibernate. I have an entity Project that contains a one-to-many relationship with Activity.

I encounter the following error:


java.lang.IllegalStateException: Failed to execute CommandLineRunner
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:773) ~[spring-boot-3.1.0.jar:3.1.0]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:754) ~[spring-boot-3.1.0.jar:3.1.0]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:318) ~[spring-boot-3.1.0.jar:3.1.0]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1305) ~[spring-boot-3.1.0.jar:3.1.0]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1294) ~[spring-boot-3.1.0.jar:3.1.0]
    at org.classroomcreative.ClassRoomCreativeStart.main(ClassRoomCreativeStart.java:25) ~[classes/:na]
Caused by: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: org.classroomcreative.domain.Project.activities: could not initialize proxy - no Session
    at org.hibernate.collection.spi.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:635) ~[hibernate-core-6.2.2.Final.jar:6.2.2.Final]
    at org.hibernate.collection.spi.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:218) ~[hibernate-core-6.2.2.Final.jar:6.2.2.Final]
    at org.hibernate.collection.spi.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:615) ~[hibernate-core-6.2.2.Final.jar:6.2.2.Final]
    at org.hibernate.collection.spi.AbstractPersistentCollection.read(AbstractPersistentCollection.java:136) ~[hibernate-core-6.2.2.Final.jar:6.2.2.Final]
    at org.hibernate.collection.spi.PersistentBag.toString(PersistentBag.java:610) ~[hibernate-core-6.2.2.Final.jar:6.2.2.Final]
    at java.base/java.lang.StringConcatHelper.stringOf(StringConcatHelper.java:453) ~[na:na]
    at org.classroomcreative.domain.Project.toString(Project.java:12) ~[classes/:na]
    at org.classroomcreative.ClassRoomCreativeStart.lambda$demo$0(ClassRoomCreativeStart.java:48) ~[classes/:na]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:770) ~[spring-boot-3.1.0.jar:3.1.0]
    ... 5 common frames omitted

In my Project class, I have the following configuration for the one-to-many relationship:


@Data
@Entity
@NoArgsConstructor
@AllArgsConstructor
public class Project {


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

    String target;

    List<String> images;

    @OneToMany(mappedBy = "project", cascade = CascadeType.ALL, orphanRemoval = true)
    List<Activity> activities;

}

The Activity class is also defined as an entity with the following configuration:

@Data
@AllArgsConstructor
@NoArgsConstructor
@Entity
public class Activity {

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

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "project_id")
    Project project;

    String development;

    String targets;

    String basicKnowledge;

    String assessment;
}

And this is the test I'm running and getting the error:

@SpringBootApplication
@Slf4j
public class ClassRoomCreativeStart {
    public static void main(String[] args) {
        SpringApplication.run(ClassRoomCreativeStart.class, args);
    }


    @Bean
    public CommandLineRunner demo(ProjectRepository projectRepository, ActivityRepository activityRepository) {
        return (args) -> {
            ProjectServiceImpl service = new ProjectServiceImpl(projectRepository);

            Activity activity1 = new Activity();
            activity1.setTargets("Target for Activity 1");

            Project project = new Project();
            project.setTarget("Sample Project");
            project.setActivities(List.of(activity1));

            service.saveProject(project);



            // Retrieve projects and activities
            log.info("Projects found with findAll():");
            log.info("-------------------------------");
            for (Project p : service.getProjects()) {
                log.info(p.toString());
            }

        };
    }
}

My service is:

@Service
public class ProjectServiceImpl {
    private final ProjectRepository repository;

    public ProjectServiceImpl(ProjectRepository repository){
        this.repository = repository;
    }

    @Transactional
    public Project saveProject(Project project){
        return repository.save(project);
    }

    @Transactional(readOnly = true)
    public List<Project> getProjects(){
        return repository.findAll();
    }
}

I have tried all the solutions mentioned in How to solve the “failed to lazily initialize a collection of role” Hibernate exception, but the issue persists.

score 0 · Accepted Answer · answered Jul 20 '23 at 22:42

0

adding fetchType of Eager in the @OneToMany end should solve lazy initialization problem

@OneToMany(fetch = FetchType.EAGER, mappedBy = "project", cascade = CascadeType.ALL, orphanRemoval = true)
    List<Activity> activities;

but you also need to override toString method of activity class to prevent circular dependency between them (exclude project attribute from toString method in the Activity class)

answered Jul 20 '23 at 22:42

Ahmed Nabil

457
1
9

Thanks @Ahmed Nabil for your answer, when I set the load eager when I print the project object the activities are empty. Example:`Project(id=1, target=Sample Project, images=null, activities=[])`. – Fjgonmir Jul 21 '23 at 16:37
sorry for late answer, you are using bi-directional relationship between Project and activities, so you should always keep synch between the 2 ends, so whenever you are adding activity to activities List, you should also setProject on that activity – Ahmed Nabil Jul 25 '23 at 06:09
Thanks , working – Fjgonmir Jul 27 '23 at 21:23
Happy to hear that. U should mark it as accepted answer if it helps – Ahmed Nabil Jul 28 '23 at 05:23

Failed to execute CommandLineRunner - Hibernate LazyInitializationException

1 Answers1