Applications which run under an EJB container have their transactions managed by the container using the Java Transaction API (JTA). Applications which run outside an EJB container can make use of resource-local transactions provided by the EntityManager interface. In Chapter 6 we saw an example of resource local transactions. In this chapter we looked at container managed transactions (CMT) using the JTA.

We described the ACID properties a transaction must possess before moving onto CMT transaction attributes. These were SUPPORTS, NOT_SUPPORTED, REQUIRED, REQUIRES_NEW, MANDATORY, NEVER.

We covered the SessionSynchronization interface: this provides stateful session beans using CMT control over commits and rollbacks.

We described doomed transactions before moving onto concurrency and locking topics. We discussed isolation levels, the third ACID property. We described three problems that occur with concurrent transactions: the dirty read, unrepeatable read and phantom read problems...