Raveendra Ponnam

• Apr 29th, 2005

The following steps describe the life cycle of an entity bean instance  An entity bean instances life starts when the container creates the instance using newInstance and then initialises it...

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Answered by Jey on 2005-05-08 12:30:37: Message Driven Bean (MDB) is an enterprise bean which runs inside the EJB container and it acts as Listener for the JMS asynchronous message . It does not have Home and Remote interface as Session or Entity bean. It is called by container when container receives JMS asynchronous message. MDB has to implement MessageListener which has a method onMessage(Message...

Jey

• May 8th, 2005

Message Driven Bean (MDB) is an enterprise bean which runs inside the EJB container and it acts as Listener for the JMS asynchronous message . It does not have Home and Remote interface as Session or...

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Answered by Nikhil on 2005-05-11 01:52:59: The lifetime of an MDB instance is controlled by the container. Only two states exist: Does not exist and Ready , as illustrated in the following figure:     The life of an MDB instance starts when the container invokes newInstance() on the MDB class to create a new instance. Next, the container calls setMessageDrivenContext() followed...

Nikhil

• May 11th, 2005

The lifetime of an MDB instance is controlled by the container. Only two states exist: Does not exist and Ready , as illustrated in the following figure:     The life of an MDB ins...

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John

• May 3rd, 2005

We can describe the following common rules for choosing whether to use remote client view or local client view:  When you will potentially use a distributed environment (if your enterprise b...

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Answered by Jey on 2005-05-08 18:01:39: There are six transaction attributes that are supported in EJB. 1. NotSupported 2. Supports 3. Required 4. RequiresNew 5. Mandatory 6. Never

Jey

• May 8th, 2005

There are six transaction attributes that are supported in EJB. 1. NotSupported 2. Supports 3. Required 4. RequiresNew 5. Mandatory 6. Never

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Answered by Jey on 2005-05-08 11:55:29: Activation and Passivation is appilicable for only Stateful session bean and Entity bean.   When Bean instance is not used for a while by client then EJB Container removes it from memory and puts it in secondary storage (often disk) so that the memory can be reused. This is called Passivation.  When Client calls the bean instance again then...

Jey

• May 8th, 2005

Activation and Passivation is appilicable for only Stateful session bean and Entity bean.   When Bean instance is not used for a while by client then EJB Container removes it from memory an...

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suresh chowdary

• Jun 14th, 2005

Pooling of instances.  in stateless session beans and Entity Beans server maintains a pool of instances.whenever server got a request from client, it takes one instance from the pool and serves the client request.

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Answer posted by Mohan on 2005-05-21 17:07:03: JNDI Context Provides a mechanism to lookup resources on the network Initial Context constructor provides the initial context. Session Context has all the information a session bean would require from the container Entity Context has all the information that an Entity bean would need from a container Ejb Context contains the information...

Mohan

• May 21st, 2005

JNDI Context Provides a mechanism to lookup resources on the network Initial Context constructor provides the initial context. Session Context has all the information a session bean would re...

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Answer posted by Mohan on 2005-05-21 17:14:47: CMR - Container Managed Relationships allows the developer to declare various types of relationships between the entity beans

Mohan

• May 21st, 2005

CMR - Container Managed Relationships allows the developer to declare various types of relationships between the entity beans

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Answer posted by Mohan on 2005-05-21 17:15:36: CMR and sub classing of the CMP bean by the container

Mohan

• May 21st, 2005

CMR and sub classing of the CMP bean by the container

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Srinivas Jadcharla

• Jul 18th, 2005

The EJB container provides services to EJB components. The services include transaction, naming, and persistence support.    Transaction support An EJB container must support transactions. E...

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Srinivas Jadcharla

• Jul 18th, 2005

2 types of exceptions can occur    1.System Exception - We can define some error codes the in the property file and show it to the JSP  2.Application Exception.. - We can customise the exception and show the appropriate error  

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Srinivas Jadcharla

• Jul 18th, 2005

Yes

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To have a consistent interface, so that there is no different interface that you need to implement for Stateful Session Bean and Stateless Session Bean. Both Stateless and Stateful Session Bean implement javax.ejb.SessionBean and this would not be possible if stateless session bean is to remove ejbActivate and ejbPassivate from the interface. You could argue that the two (stateful and stateless) are...

Ginni

• Jul 21st, 2005

The simple reason is to manage your resources. For eg. if you use/open any third party resource on ejbActivate, you need to make sure ejbPassivate close the connection/ release the use of resource regardless of stateful session or stateless session.

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Answered by Jey Ramasamy on 2005-05-08 20:04:33: No. This method must not contain any input parameters and cannot be overloaded as well.

Jey Ramasamy

• May 9th, 2005

No. This method must not contain any input parameters and cannot be overloaded as well.

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Ginni

• Jul 21st, 2005

Yes, you can create entity bean without impelementing the create() method. The ejbs will be instantiated by findByPK or any finder methods.

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Lavanya

• Apr 17th, 2005

EJB Architecture consists of :  a) EJB Server b) EJB containers that run on these servers, c) Home Objects, Remote EJB Objects and Enterprise Beans that run within these containers...

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Absolutely yes, but the way to do that depends on the Exception, since there are no standards for that. Some examples: ·When you have an javax.ejb.EJBException, you can use the getCausedByException() that returns a java.lang.Exception. ·A java.rmi.RemoteException there is a public field called detail of type java.lang.Throwable ·With a java.sql.SQLException you need to use the method getNextException()...

manoj b raut

• Oct 26th, 2005

100% depends upon the mode of execution .

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Rajesh Rokkam

• Jun 3rd, 2005

Yes,undefined primary keys are possible with Entity Beans.The type is defined as java.lang.Object.

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RajeshRokkam

• Jun 3rd, 2005

Two Entity Beans are said to be Identical,if they have the same home inteface and their primary keys are the same.To test for this ,you must use the component inteface's isIdentical() method.

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