What is bean-managed transaction ?

In the context of Java EE (Enterprise Edition), specifically for Enterprise JavaBeans (EJB), a bean-managed transaction (BMT) refers to a situation where the management of transaction boundaries is handled explicitly by the enterprise bean code rather than being automatically managed by the container.

In a bean-managed transaction, the enterprise bean developer is responsible for demarcating the transaction boundaries explicitly using the javax.transaction.UserTransaction interface. This allows for fine-grained control over transaction management within the business methods of the enterprise bean.

Here’s a basic outline of how bean-managed transactions work:

1. The enterprise bean begins a transaction by calling UserTransaction.begin().
2. The business logic is executed within the transaction boundary.
3. The enterprise bean decides whether to commit or roll back the transaction based on business logic.
4. The enterprise bean calls UserTransaction.commit() to commit the transaction or UserTransaction.rollback() to roll back the transaction.

Bean-managed transactions provide flexibility to developers, allowing them to have more control over the transactional behavior of their enterprise beans. However, it also requires a good understanding of transaction management and careful coding to ensure proper transactional integrity.

It’s worth noting that the alternative to bean-managed transactions is container-managed transactions (CMT), where the container automatically manages the transaction boundaries, and the developer doesn’t have to explicitly handle transaction management in the code. The choice between BMT and CMT depends on the specific requirements and design considerations of the application.