QueryDSL is a popular framework that provides you a Java API to create queries for relational databases and other data stores. If you’re familiar with JPA’s Criteria API, you might think that it does the same as QueryDSL and that you don’t need to learn about another framework. But I recommend you give QueryDSL a…
Hibernate and the JPA specification define multiple generators to create unique primary key values. An obvious question when learning about these generators is if you can apply them to basic attributes as well. Unfortunately, the answer is no. But Hibernate’s ValueGenerator provides an easy-to-use alternative. As I will show you in this article, you can…
With the T getReference(Class<T> entityClass, Object primaryKey) and the T find(Class<T> entityClass, Object primaryKey) method, JPA’s EntityManager seems to provide 2 methods that do the same. Both of them seem to get an entity by its primary key from the database. There obviously is a difference between the 2 methods. An established and well-defined API…
By default, Hibernate loads all entity objects in read-write mode. It performs dirty checks to detect changes it needs to persist in your database for each of them. That makes entities very easy to use, but it also creates an overhead if you don’t want to change anything. You can avoid this by setting Hibernate’s…
I recently got a lot of questions about JPA 3.0, and since EclipseLink and Hibernate now offer full support for it, it’s time to take a closer look at the latest update of the specification. As part of the transformation from Java EE to Jakarta EE, the Java Persistence API (JPA) was renamed to Jakarta…
