ByThorben JanssenYou probably learned that you should use FetchType.LAZY for all of your associations. It ensures that Hibernate initializes an association when you use it and doesn’t spend any time getting data you don’t need. Unfortunately, this introduces a new issue. You now need to use a JOIN FETCH clause or an EntityGraph to fetch the…
ByThorben JanssenEntityGraphs and JOIN FETCH clauses provide an easy and efficient way to fetch an entity and initialize its associations. But if you try to use it with a domain model that uses inheritance, you will quickly run into an issue: You can’t use this approach in a polymorphic query to fetch an association that’s defined…
ByThorben JanssenThe LazyInitializationException is one of the most common exceptions when working with Hibernate. There are a few easy ways to fix it. But unfortunately, you can also find lots of bad advice online. The proclaimed fixes often replace the exception with a hidden problem that will cause trouble in production. Some of them introduce performance…
ByThorben JanssenChoosing the right projection when selecting data with JPA and Hibernate is incredibly important. When I’m working with a coaching client to improve the performance of their application, we always work on slow queries. At least 80% of them can be tremendously improved by either adjusting the projection or by using the correct FetchType. Unfortunately,…
ByThorben JanssenWhen you start learning and using Hibernate and JPA, the number of annotations might be overwhelming. But as long as you rely on the defaults, you can implement your persistence layer using only a small subset of them. After you have mastered the basic annotations, you can take a look at additional customization options. You…