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.

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Priyabrata

  • Feb 23rd, 2006
 

J2EE application server in general or Weblogic appliction server in particular provide services such as security, data integration and resource management. So the developers can concentrate only on the functionality they need to implement.

Also since these servers are written according to the j2EE specifications, any application written in J2EE can be put on those servers with out doing code modifications.

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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, using EJBs addresses many of the issues you would find by using simple Java objects, such as scalability, lifecycle management, and state management.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, using EJBs addresses many of the issues you would find by using simple Java objects, such as scalability, lifecycle management, and state management.

EJB's can be in divided in three main categories - Session , Entity Beans and Message driven Beans.

Session Beans are again divided further into Stateful and Stateless.

StatefulSessionBean(SSB) is used when client state has to be maintained. StatelessSB is used when to many clients are to be served and duration and state with is not longer.

Entity Beans are furhter divided to BMP and CMP.

In container-managed persistence, the container is responsible for making the right calls to the persistence storage mechanism (RDBMS, XML database, ASCII files, and so on), and ensuring the synchronization between the entity bean and the physical storage.

BMP :  Bean-managed persistent entity bean is an entity bean that must pe persisted by hand, in other words the component developer must write code to translate the in memory fields into an underlying data store. You have to handle persistent operations yourself - including saving, loading, and finding data within the entity bean.

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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 different servers without modifying the code, ie all servers implementing the J2EE contract will deploy the application without any modification.

One such example of a J2EE compliant server is weblogic server. It hides or shields the developer from being concerned about the aspects of making the application run, other than the application business logic. The developer need not worry about the transaction services or networking issues or security implementation etc. All these services will be taken care of by the server. So from the software development view, the only work the developer has to be concerned with is coding the business logic o fthe aplication and leave the rest to the server. The servers bring with them tested and robust functionalities, and hence the developer need to be conserned with the defect arising out of the application logic only. This eases the entire software development lifecycle.

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