// Fast: Fetches only what you need, immutable, no persistence context overhead List<PostDTO> posts = entityManager.createQuery("select new com.dto.PostDTO(p.id, p.title) from Post p", PostDTO.class).getResultList(); Why is this faster than the book's PDF suggests? Because you remove the Entity Manager from the equation. No snapshots. No comparisons. Just data transfer. Vlad Mihalcea’s book is fantastic, but the concepts evolve faster than print. If you search for a static PDF, you freeze your knowledge in time.
Here is the uncomfortable truth:
Most developers do this:
If you have typed "high-performance java persistence book pdf" into Google, you belong to a specific tribe of developer. You are not a beginner. You have already felt the sting of a N+1 query in production. You have watched a seemingly simple @OneToMany annotation bring a microservice to its knees. high-performance java persistence book pdf