I use @Version for Student that has a list of courses that do not have @Version.

@Entity
Class Student {


....

List<Course> getCourses();

@Version
public Integer getVersion() {
}

}

@Entity
Class Course {

}

When I added a course to a student, then increase the student's version without reloading the student from database to match the version in database.

The Student has other lazy property, so at some point I used
session.lock(student, LockMode.NONE);
to connect the detached entity to session in order to fetch lazy properties.

But I got exception:
"entity has dirty collection"

How Lock works? How does Hibernate know dirty collection? In term of version, they match version in persistence.

Thanks for help.

It happend without @Version too.

@OneToMany relation

create one course, persist it
add it to collection, and then
merge the owning entity Student

No issue.
but session.lock(student, LockMode.NONE)

throw:
org.hibernate.HibernateException: reassociated object has dirty collection

Thanks for ideas.