Hibernate Framework Hibernate Transactions 2

Question 1

Which LockMode acquires a pessimistic write lock in Hibernate?

Accepted Answer

LockMode.PESSIMISTIC_WRITE

Answer

LockMode.PESSIMISTIC_WRITE requests a SELECT FOR UPDATE lock, preventing other transactions from reading or writing the row.

Question 2

What is a StaleObjectStateException in Hibernate?

Accepted Answer

Thrown when optimistic locking detects a concurrent modification

Answer

StaleObjectStateException is thrown when a commit detects that another transaction has already modified the same versioned entity.

Question 3

What is the difference between session.save() and session.persist() in Hibernate?

Accepted Answer

save() returns the generated ID immediately; persist() is JPA-standard and returns void

Answer

save() immediately inserts the entity and returns the generated identifier, while persist() is the JPA-standard method that schedules the insert and returns void.

Question 4

What does session.merge() do in Hibernate?

Accepted Answer

Copies state from a detached entity into a new managed entity

Answer

merge() takes a detached entity, copies its state into a managed entity with the same identifier, and returns the managed instance.

Question 5

What are the four entity states in Hibernate?

Accepted Answer

Transient, Persistent, Detached, Removed

Answer

Hibernate entities cycle through four states: transient (not associated), persistent (managed), detached (was managed), and removed (scheduled for deletion).

Hibernate Framework Practice Test

Hibernate Framework Practice Test

Hibernate Framework Hibernate Transactions 2