org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role

Question

I have table called category which has parent category field. I am using that field to get the sub categories. I have checked the answer for the similar question, the suggestion was (fetch = FetchType.EAGER). But I want to load it as LAZY because it is circular dependency. (Pointing to the same table again).

@Entity
@Table(name = "CATEGORY")
public class Category implements Serializable {
    @Id
    @Column(name = "ID")
    @GeneratedValue
    private Integer id;

    @Column(name = "CATEGORY_NAME", nullable = false, length = 40)
    private String name;

    @Column(name = "DESCRIPTION", nullable = false, length = 255)
    private String description;

    @Column(name = "DATE_CREATED", nullable = false)
    private Date dateCreated;

    @Column(name = "UUID", nullable = false, length = 40)
    private String uuid;

    @ManyToOne
    @JoinColumn(name = "PARENT_CATEGORY_ID")
    private Category parentCategory;

    @OneToMany(mappedBy = "parentCategory")
    private Collection<Category> subCategories = new LinkedHashSet<Category>();
}

The error is:

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.hemanths.expense.manager.api.hibernate.entity.Category.subCategories, could not initialize proxy - no Session
    at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:566)
    at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:186)
    at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:545)
    at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:124)
    at org.hibernate.collection.internal.PersistentBag.iterator(PersistentBag.java:266)

Can someone help me find the solution?

Answer 1

Looking at your stack trace, it looks like this is a session management issue. Try looking at where you are opening your session, and what SessionContext you are using?