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What is CMT transaction?
When you use container-managed transactions (CMT), your EJB delegates to the container the responsibility to ensure that a transaction is started and committed when appropriate. All session and message-driven beans may use CMT. EJB 2.1 entity beans must use CMT.
Is distributed transaction supported by EJB?
The EJB specification allows for distributed transactions that span multiple resources (such as databases) and supports the two-phase commit protocol for both EJB CMP 2.0 and EJB CMP 1.1.
What is CDI and EJB?
The “C” in CDI is the main difference between EJB beans and managed CDI beans. CDI-managed beans are contextual and EJB beans are not. Managed beans in CDI live in well-defined scope. They are created and destroyed on demand by the container. The CDI container manages all beans inside the scope automatically for you.
What is EJB transaction?
EJB Container/Servers are transaction servers and handles transactions context propagation and distributed transactions. Transactions can be managed by the container or by custom code handling in bean’s code. Bean Managed Transactions − In this type, the developer manages the life cycle of transaction states.
What are the different types of EJB?
There are three types of EJBs: session beans, entity beans, and message-driven beans.
What is the valid reason behind a stateful session bean instead of a stateless session bean?
Because they can support multiple clients, stateless session beans can offer better scalability for applications that require large numbers of clients. Typically, an application requires fewer stateless session beans than stateful session beans to support the same number of clients.
Which of the following is correct about a isolated transaction in EJB?
Q 4 – Which of the following is correct about a Isolated transaction in EJB? A – If any of work item fails, the complete unit is considered failed. Success meant all items Page 2 executes successfully.
What does @singleton annotation do?
@Singleton (and any other scope annotation) makes your class a single instance in your dependencies graph (it means that this instance will be “singleton” as long as Component object exists).
Is EJB still used 2020?
6 Answers. EJB3 is a vast improvement over previous versions. It’s still technically the standard server-side implementation toolset for JavaEE and since it now has none of the previous baggage (thanks to annotations and Java Persistence), is quite usable and being deployed as we speak.
Why the particular EJB is used?
EJB beans are specifically designed to implement the business logic of your application. As such they provide services that are often needed when implementing such logic, such as transactions, injecting of the entity manager (used for JPA, the Java Persistence API) and pooling of beans.