ByThorben JanssenWith 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…
ByThorben JanssenHibernate generates proxies to provide lazy loading for to-one associations, and you can use them to improve the performance of some of your write operations. You might have seen the class names of these proxies in your debugger or some log messages. They consist of the name of your entity class and a postfix that…
ByThorben JanssenHibernate provides 2 proprietary features that enable you to define additional filter criteria that Hibernate applies to every query that selects a specific entity class. This article will show you how to use the @FilterDef and @Filter annotations, which is the more flexible approach. You can activate and deactivate filter definitions for your current session…
ByThorben JanssenJPA and Hibernate make it very easy to model associations between entities. You can model associations between 2 concrete classes or model a polymorphic association to an inheritance hierarchy. These mappings are more than sufficient for almost all of your association mappings. But sometimes, you might want to model a polymorphic association to independent entity…
ByThorben JanssenJPA and Hibernate provide 3 main options to map a Collection. If it’s a Collection of other entities, you can model it as a to-many association. This is the most common mapping. But you can also map it as an @ElementCollection or as a basic type. In this article, I will show you all 3…