1. Persistence Context
In this article we will cover Container vs Application Managed EntityManager (Persistence Context) and its relationship with JTA or RESOURCE LOCAL transaction management.
In this article we will cover the differences between TRANSACTION and EXTENDED Persistence Context (Entity Manager).
2. Entity Relationships
This article explains why do the Java Persistence API (JPA) often generates additional queries while dealing with OneToOne relationships
3. Locking
This article covers database optimistic locking in general and also demonstrates how to implement optimistic locking in Java Persistence API (JPA) entities by using the @Version annotation
This article covers the optimistic and pessimistic locking mechanisms available in the Java Persistence API (using LockModeType)