In Relation To

For our Portuguese readers, this article gives a very good introduction to database transactions and isolation levels.

Hibernate Query Cache can help you reduce the number of queries that are sent to the database, but you have to pay attention to the entity cache expiration policy, as otherwise, you might bump into N+1 query problems.

The Hibernate @Immutable annotation allows you to optimize the Persistence Context size and the dirty checking mechanism if entities should never be modified. For more details, check out this article.

When mapping bidirectional associations, it is very important to synchronize both sides of the association. Otherwise, you might encounter inconsistencies which prevent entity state transitions from being propagated to the database.

If you’re using Spring Boot, check out this tutorial about mapping a @OneToMany JPA association.

With Hibernate 5.2.17, you can now use the @PrePersist and @PreUpdate entity listeners even on embeddable types. For more details, check out this article.

With Hibernate, you can map a @ManyToOne association using the result of a query, as explained in this article.

There were several Hibernate project releases since the last newsletter: