WebLogic: The Definitive Guide

EJBs and Transactions

WebLogic’s EJB container supports EJBs that can participate in distributed transactions. EJBs deployed to WebLogic Server can be involved in JTA transactions that may cover updates to multiple data stores. A single transaction can span multiple EJBs deployed to multiple WebLogic instances. The EJBs also can participate in the two-phase commit protocol, which coordinates transactional updates across two or more resource managers.

For entity beans, it is the EJB container that always manages the transaction boundaries. Session and message-driven beans support both bean-managed and container-managed transactions. In the case of bean-managed transactions, the EJB implementation must explicitly supervise the transaction boundaries. Typically, the EJB code will acquire a reference to the UserTransaction object from the EJBContext, and then make explicit calls to the begin, commit, and rollback methods to mark the start and completion of the transaction. For container-managed beans, the EJB container manages all transaction boundaries. You can specify the transaction attributes for the EJB methods in the ejb-jar.xml descriptor file for the EJB component. The default transaction setting for an EJB method is Supports. In other words, all EJB methods are capable of participating in a transaction, if one exists. Of course, you must not use the UserTransaction interface within an EJB method that supports container-managed transactions.

Distributed transactions

A client ...