JPA / Hibernate实体类和同步的最佳实践是什么？

It seems like most examples of JPA/Hibernate entity bean classes I've seen do no explicit synchronization. Yet, it is possible to call getters/setters on those objects in the context of building up a transaction. And it's possible for those methods to be called across multiple threads (although maybe that's unusual and weird). It seems like most examples of JPA/Hibernate en