Persistencecontext

JPA specification defines few types of EntityManagers / Persistence Contexts. We can have: extended and transactional-scoped EntityManagers, container-managed or application-managed EntityManagers. JTA or resource-local EntityManager, Besides the above distinction, we also have two main contexts in which EntityManager / Persistence Context can exist – Java EE and Java SE. Not every option is available for Java EE and not every is possible in Java SE. In the rest of the post I refer to the Java EE environment....

Recently, I’ve bumped into few posts on StackOverflow where people tend to compare container managed EntityManager instances (so the one injected by the container) by invoking EntityManager#toString() method. I’ve felt that it’s fundamentally wrong to compare EntityManager instances without knowing how they’re managed by the JPA provider or the Server Application. And what if this behaviour differs between Application Server vendors? The JPA provider provides an implementation of EntityManager – that’s obvious....