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EJB Deployment Process
Knowing that EJB encapsulates business logic in a web application, how does EJB actually do it in a application server ?
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Comparison between ejb2.0 and ejb3.0
am577
- Dec 27th, 2009
The deployment descriptors are no longer required; everything can be accomplished using metadata annotations. The CMP (Container Managed Persistence) has been simplified; it is now more l...
thomaskm
- Apr 27th, 2007
The major differences i have seen between EJB 2.x and EJB 3.0 versions are as follows :- 1). Removal of home interface enabled simple lookup process in ejb 3.0 2). EJB deployment descriptors are not r...
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How can we update a row in the db using entity bean?
uppulafaq
- Jan 21st, 2010
Yes, we can update a row using entity bean.ejbStore() will do that.in BMP you have to write code to update the row.
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What is EJB
opbehera
- Feb 8th, 2010
EJB is a distributed technology i.e capable of developing java based distributed applications, enterprise application & heavy weight business component giving the advantages of readyma...
sai.pappu
- Sep 26th, 2008
EJB is an server side component & its a WODA ( Write Once Deploy Any Where).EJB's run will under the control of EJB container.EJB is popular due to System level services provided by it.Developer can more concentrate on Business Logic due to services provided byu EJB.thanks.
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What is ACID
Answered by Jey on 2005-05-08 17:27:45: ACID is releated to transactions. It is an acronyam of Atomic, Consistent, Isolation and Durable. Transaction must following the above four properties to be a better one Atomic: It means a transaction must execute all or nothing at all. Consistent: Consistency is a transactional characteristic that must be enforced by both the transactional system...
opbehera
- Feb 8th, 2010
A - AtomocityC - ConsistencyI - IsolationD - Durability.When Transactoon(Tx) middleware service is enabled on the Businesslogic the data on the application available outside or in DB s/w&nbs...
Ritesh patni
- Jul 25th, 2005
Atomic-- should execute all or nothing...rollback come into picture Consistent--Consistency is a transactional characteristic that must be enforced by both the transactional system and the applic...
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Business Method Request
How to find who has given request (caller) to Business method of your application(SLSB)
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How do you check whether the session is active in Stateful session bean
nemashailendra
- Mar 25th, 2010
Use the callback methods ejbActivate() and ejbPassivate() to throw a user-defined message whenever the container calls these methods to activate or passivate a stateful session bean instance.
J. P. Naidu
- Jul 28th, 2005
In Stateful session bean session is not itself a separate entity. it is contained in the bean it self. So in order to check tht we need the check whether the Stateful session bean is present or not which is done by just invoking the home interface with the jndi
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Why an onMessage call in Message-driven bean is always a seperate transaction
nemashailendra
- Mar 25th, 2010
Message driven beans cannot be instantiated by a client application. The container creates the mdb instantiates an mdb each time a message is available on a jms queue. Hence by default each message is...
Anand
- Apr 26th, 2005
The MDB is stateless and inherently each message is unique with respect to the MDB. Each message needs to be processed independently. Hence the need for separate transactions
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Distributed Object using RMI-IIOP
How are parameters passed to a method of a distributed object using RMI-IIOP?
NovaCarolina
- May 12th, 2010
The parameters which are passed to remote methods will be a copy of the actual parameter objects. The basic rule is that the parameters should be Serializable or primitives. The remote JVM will get an exact copy of the objects being passed as parameters from the client JVM.
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1. How do J2EE application servers in general and the Weblogic servers in particular help software development? 2. What are EJBs? What are factors to determine which type of the EJBs to use? Give an example for each type you built recently in the projects you worked with and your reason of using that? 3. Describe how transactions are handled in EJBs. What happens to an EJB if an Exception is not caught? 4. Describe different ways of deploying EJBs to the Weblogic servers. Describe the necessary steps of deploying EJBs to the Weblogic servers for each of the methods identified above. What are the key parameters needed for the deployments?5. What are the steps to build WebServices for Weblogic application servers? Describe the necessary steps of deploying WebServices to the Weblogic servers.6. What are commonly used types of JMS subscribers? What are the steps to build the types of the JMS subscribers mentioned before? What happens if an Exception is not caught in the subscribers? 7. What is the proper way to ensure the messages are processed in order if messages are ordered entering a JMS queue? 8. What are the message selectors and how are they used?9. What will happen to the messages in a JMS queue if they do not match any one of the selectors associated with its subscribers? If JMS topics used instead of queues, will the answer be different? 10. How do you implement a priority based queue using JMS? What is the proper ways to give a group of messages higher priority? 11. If for some reason you have to delay a group of messages on a JMS queue from being processed, what is the proper way to implement it in JMS? 12. Describe the necessary steps to make a Message Driven Bean on the Weblogic server subscribe to a Foreign JMS destination, in particular if the destination is a Tibco JMS queue assuming the Tibco JMS security is turned on? 13. Describe the necessary steps to develop a XML SAX parser. Describe how XMLBean works.14. Describe how IBM MQ/JMS adaptor works. Describe the necessary steps to configure and use the IBM MQ/JMS adaptors.
NovaCarolina
- May 12th, 2010
J2EE app servers give freedom to the developer/ application deployer/ end user from vendor lockin. As far as software development is concerned, such ass servers gives flexibility in choosing between d...
Supraja
- Feb 28th, 2006
Enterprise JavaBeans (EJBs) contain the application's business logic and live business data. Although it is possible to use standard Java objects to contain your business logic and business data, usin...
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How to call ejbs from jsp?
bassem.aly
- Jun 2nd, 2010
You have two option.If the EJB is local (in the same EAR) you will use @EJBIf the EJB outside ear you will lookup in Application server context.
Rizwan
- Feb 7th, 2007
First approach is also correct. But in that approach you have use narrow method whereas in this case you dont need it. By using this approach also we can call EJB from a jsp initalContext ic=...
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Wait(), notify() and notyfyAll() methods
Why wait(), notify() and notyfyAll() methods are avialble in Object class but not in Thread class? Explain.
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Editorial / Best Answer
janswain- Member Since Sep-2008 | Sep 25th, 2008
Each object in java is associated with a lock and the wait and notify methods are not associated with a thread but with a lock, so?coupling locks and objects meant that each object should have wait and notify methods that operate on that objects lock.
Java provides a way to lock the code for a thread which is currently executing it using the synchorinized keyword, and making other threads that wish to use it wait until the first thread is finished.These other threads are placed in the waiting state .Once the first thread completes it task than it notifies others in the queue by giving the lock to JVM.Now JVM decides which thread will exceute next by its internal algo.Hence, the wait and notify methods has to be in Object class as it acquires lock and has to notify others.....tarunkgupta
- Sep 2nd, 2010
A thread having a lock on the shared object (by using synchronized constructs) can invoke these methods on that shared Object. It gives a hint to JVM scheduler to pick or block the next thread contend...
NovaCarolina
- May 12th, 2010
A lock is done on an object. It is an obect which is locked, hence these methods are characteristics of the object, hence defined in the Object class.
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What is the difference between JavaBean and EJB
Answer posted by Mohan on 2005-05-20 08:40:04: Java Beans is intra-process component where as EJB is an Inter-Process component JavaBeans is particularly well-suited for asynchronous, intra-application communications among software
sai.pappu
- Sep 12th, 2008
JavaBean :1. Low-level approach for developing re-usable components for building different Java applications (Applets, stand-alone applications etc.).2. Java Beans runs in a JVM, just like other norma...
Guest
- Dec 14th, 2005
JavaBeans- are reuseable,non-deployable components. They can't exist independently.EJB - are deployable, reuesable, server side components. They can exist independently or in integration with other components.
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Can I invoke Runtime.gc() in an EJB
Answer posted by Mohan on 2005-05-21 19:26:48: No
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What are webservices?
shahbazhafeez
- Apr 18th, 2011
Remotely hosted scalable/distributed applications/services (which process and/or store/retrieve data) such that the client does not need to execute locally on a single machine.
coolguy_krkr
- May 11th, 2008
Webservices are typically any services that can be published over the internet or on a wide range of networks so that the functionality is available to a wider audience..There is a slight differe...
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What is the difference between normal Java object and EJB
srinivask82
- Jun 11th, 2008
An EJB object is also an java object, but as it follows the EJB Specifications, it can be remotely identified in an Application server. An java object can be deployed in an application server, but can...
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What is the difference between CMP and BMP
Answered by Jey on 2005-05-08 11:32:16: CMP means Container Managed Persistence. When we write CMP bean , we dont need to write any JDBC code to connect to Database. The container will take care of connection our enitty beans fields with database. The Container manages the persistence of the bean. Absolutely no database access code is written inside the bean class. BMP means Bean Managed Persistence....
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EJB Interview Questions
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