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How to explain the special term EJB in J2EE? aiming at this problem, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

Bean Instance (Bean instance)

Bean Instance is a J2EE EJB term. Bean Instance is the instantiation where Bean is located in a container. If you compare bean to class, then Bean Instance is Java Object.

Bean-managed persistence (sustainable BMP managed by Bean itself)

The term J2EE EJB is used to describe how Enterprise Java Bean stores their state to a database or other storage mechanism. The container will cause Bean to call the EjbLoad () and EjbSave () methods of Bean.

Container (container)

A container of Bean in J2EE EJB will implement home interfaces and remote interfaces of bean. It should provide a set of utility classes to be able to hide bean instances, intervene in method calls, maintain transaction integrity and general management of bean instances pools. Although the Ejb rule states that a container must manage more than one bean, there is usually only one bean per container.

Container-managed demarcation

For an enterprise bean, whenever one of the business methods is called, the container automatically initiates a new transaction. When the business method is completed, the transaction is over. The form in which the container initiates the transaction is determined by the transaction properties of the bean, or, if specified, by the business method itself.

Container-managed persistence (Container managed persistent CMP)

Bean developers can delegate containers to record the * status of Bean. The status of the Bean must be obtained by many public Fields in the Bean. The container ensures that these public fields are correct before any bean method is awakened. Public fields must be defined in deployment descriptor before container classes is generated.

Entity beans

Entity beans stands for recognizable perpetual objects. A typical example is that it can represent individual rows in a relational database. Of course, it can also be a file in the file system, or any other identifiable data.

Home

Every Enterprise Bean in J2EE EJB, whether Session or Entity bean, has an interface that allows the client to create and remove a bean instance. In the case of Entity, home interface provides ways to allow clients to use a bean instance for location. This interface follows the rules of Java RMI interface. Each home interface inherits from a remote interface, EJBHome.

Remote

The remote interface of a bean in J2EE EJB describes a collection of methods available for client calls in a bean instance. This interface follows the rules of Java RMI interface. Each remote interface inherits from a remote interface, EJBObject.

Session beans

Session beans is established by particular client. If a specified idle time called timeout has elapsed, it no longer exists.

Session synchronization

Session beans can selectively implement Session Synchronization interface. This allows Session beans to be notified before and after the transaction will be completed. Session bean can use the beforeCompletion () method to reject the successful completion of a transaction, and can use afterCompletion () to determine whether a transaction is successful or not.

This is the answer to the question about how to explain the special term EJB in J2EE. I hope the above content can be of some help to you. If you still have a lot of doubts to be solved, you can follow the industry information channel for more related knowledge.

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