Stateless Session Bean

Table 4.2. Operations allowed in the methods of a stateless session bean.

Given a list of scenarios, identify which will result in an ejbRemove method not being called on a bean instance.

The Bean Provider CANNOT assume that the Container will always invoke the ejbRemove() method on a session bean instance. The following scenarios result in ejbRemove() not being called on an instance:

• A crash of the EJB Container.
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• A SYSTEM (java.lang.RuntimeException (or subclass), javax.ejb.EJBException, java.rmi.RemoteException, failure to obtain a database connection, JNDI exceptions) exception thrown from the instance’s method to the Container.
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• A TIMEOUT of client inactivity while the instance is in the passive state. The timeout is specified by the Deployer in an EJB Container implementation specific way.

If the session bean instance allocates resources in the ejbCreate< METHOD >(...) method and/or in the business methods, and normally releases the resources in the ejbRemove() method, these resources WILL NOT be automatically released in the above scenarios. The application using the session bean should provide some clean up mechanism to periodically clean up the unreleased resources.

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Author: Mikalai Zaikin. Please Click Here to visit Authors site for any updates and changes to the study notes.

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