QueryDsl fetch lazy property

Issue

I have a property which is usually fetched lazily:

@Entity
class Version(...,
              @Basic(fetch = FetchType.LAZY)
              @Type(type = "text")
              var mappings: String? = null) {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private val id = 0
}

But sometimes I need to fetch it eagerly. How can I do this with QueryDsl? This is what I currently have:

JPAQuery<Any>(entityManager).from(QVersion.version)
        .where(...)
        .select(QVersion.version)
        .fetchOne()

But this results in a Exception when I try to access the property later:

org.hibernate.LazyInitializationException: Unable to perform requested lazy initialization [Version.mappings] - no session and settings disallow loading outside the Session

Solution

There is a very simple solution for this: .fetchAll()

JPAQuery<Any>(entityManager).from(QVersion.version)
        .fetchAll()  // <- here
        .where(...)
        .select(QVersion.version)
        .fetchOne()

Related hibernate documentation:

If you are using property-level lazy fetching (with bytecode instrumentation), it is possible to force Hibernate to fetch the lazy properties in the first query immediately using fetch all properties.

Answered By - F43nd1r