Important EJB Interview Questions

Important EJB Interview Questions:

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• 1). What are the Differences between EJB 3.0 and EJB 2.1?
• 2). What are the key features of the EJB technology?
• 3). What is the difference between EJB and RMI
• 4). What are the ways for a client application to get an EJB object?
• 5). What are the different kinds of enterprise beans?
• 6). What is Entity Bean?
• 7). Why does EJB needs two interfaces(Home and Remote Interface)?
• 8). What is an EJB Context?
• 9). Does the container create a separate instance of the generated EJBHome and EJBObject classes?
• 10). What's difference between httpsession and EJB session bean ?
• 11). What are the key benefits of the EJB technology?
• 12). Why do we have a remove method in both EJBHome and EJBObject?
• 13). What are the services provided by container?
• 14). Is it possible to share an HttpSession between a JSP and EJB? What happens when I change a value in the HttpSession from inside an EJB?
• 15). What is the difference between a Coarse Grained? Entity Bean and a Fine Grained? Entity Bean?
• 16). Does Stateful Session bean support instance pooling?
• 17). What are the Interfaces need to create to implement Session Bean with Exmaple?
• 18). How many EJB Objects are created for a Bean?
• 19). What are the parameters must follow for Session Bean ?
• 20).When you will chose Stateful session bean and Stateless session bean?
• 21). What is the difference between Stateful session bean and Stateless session bean?
• 22). What are the callbacks method in Session Bean ?
• 23). How is Stateful Session bean maintain their states with client?
• 24). What is the free pool?
• 25). Without home and remote interfaces cant we implement ejb?
• 26). When are stateless EJBs passivated?
• 27). Is method overloading allowed in EJB?
• 28). What is handle and why it is used in EJB?
• 29). Implement Local and Remote Interfaces in EJB?
• 30). How can I call one EJB from inside of another EJB?
• 31). What is the difference between Message Driven Beans and Stateless Session beans
• 32). Can you control when passivation occurs?
• 33). How to call any EJB from a servlet/JSP/Java Client?
• 34). Can the primary key in the entity bean be a Java primitive type such as int?
• 35). What are the methods of Entity Bean?
• 36). What is the difference between Container-Managed Persistent (CMP) bean and Bean-Managed Persistent(BMP) ?
• 37). Can Entity Beans have no create() methods?
• 38). What is bean managed transaction?
• 39). What are transaction isolation levels in EJB?
• 40). What is the difference between ejbCreate() and ejbPostCreate
• 41). What is the difference between sessioncontext and entitycontext?
• 42). What is the difference between ejbStore() and ejbLoad()?
• 43). What is the difference between EAR, JAR and WAR file?
• 44). How to implement an entity bean which the PrimaryKey is an autonumeric?
• 45). Is Decorator an EJB design pattern?
• 46). What is lazy loading?
• 47). What is Message Driven Bean?
• 48). What is CMR?
• 49). Can a Session Bean be defined without ejbCreate() method?
• 50). What are the optional clauses in EJB QL?
• 51). Can I use session beans and hibernate (instead of entity beans) for persitance?
• 52). If session has thrown ApplicaitonException would you use EJBContext. setRollBackOnly method?
• 53). What is the difference between activation and passivation?
• 54). How do you check whether the session is active in Stateful session bean ?
• 55). What is the difference between find and select methods in EJB?
• 56). What is the difference between local interface and remote interface?
• 57). Why CMP beans are abstract classes?
• 58). What is the difference between normal Java object and EJB?
• 59). What is abstract schema?
• 60). What is clustering. What are the different algorithms used for clustering?
• 61). Why did I get a LockTimedOutException?
• 62). What is the life cycle of MDB?
• 63). Can an entity bean be a listener for JMS messages?
• 64). What is Entity Bean. What are the various types of Entity Bean?
• 65). What is IIOP ?
• 66). Why don't stateful session beans have a pool?
• 67). Without using entity beans can we do database transactions?
• 68). What is the use of using session facade design pattern in EJB'S?
• 69). What is the difference between session and entity beans? When should I use one or the other?
• 70). Is it possible to share an HttpSession between a JSP and EJB? What happens when I change a value in the HttpSession from inside an EJB? –
• 71). What is EJB role in J2EE?
• 72). What are Container-Managed Transactional attributes ?
• 73). How is persistence implemented in enterprise beans?
• 74). Are we allowed to change the transaction isolation property in middle of a transaction?
• 75). For Entity Beans, What happens to an instance field not mapped to any persistent storage, when the bean is passivated?
• 76). What is a Message Driven Bean, what functions does a message driven bean have and how do they work in collaboration with JMS?
• 77). What is the advantage of putting an Entity Bean instance from the Ready State to Pooled state?
• 78). What is Session Bean?
• 79). If my session bean with single method insert record into 2 entity beans, how can I know that the process is done in same transaction (the attributes for these beans are Required)
• 80). Can i map more than one table in a CMP?
• 81). Difference between SessionBean remove() and EntityBean remove() method?
• 82). Does each stateless session bean have its own EJBObject?

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