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EJB Interview questions


Total available count: 73
Subject - Java Technologies
Subsubject - EJB
1
Explain the different Transaction Attributes and Isolation Levels with reference to a scenario?
2
How is the passivation of Entity beans Managed?
3
How do I automatically generate primary keys?
4
How do you implement callbacks in EJB?
5
Which fields in beans should be public?
6
What happens when two users access an Entity Bean concurrently?
7
Can beans use stored procedures in a database?
8
What's an .ear file?
9
What is an EJB primary key? How is it implemented when the database doesn't have a primary key?
10
What classes does a client application need to access EJB?
11
How does EJB support polymorphism?
12
Why are beans not allowed to create their own threads?
13
Can I use Threads in a enterprise bean?
14
How should complex find operations be implemented?
15
Does the EJB programming model support inheritance?
16
While deploying CMP entity beans, which fields in the bean are container-managed and how are they identified?
17
What makes a Java class an enterprise bean?
18
How do enterprise beans access native libraries?
19
Is entity data persisted at the end of a transaction or at any time?
20
What are the constraints or drawbacks of container managed EJB's?
21
How does an entity bean obtain a JTA UserTransaction object?
22
Is it possible for a stateless session bean to employ a JTA UserTransaction object?
23
How does an enterprise bean that uses container-managed transactions obtain a JTA UserTransaction object?
24
How does a session bean obtain a JTA UserTransaction object?
25
Do JTS implementations support nested transactions?
26
How does a client application create a transaction object?
27
How does passivation work in stateful session beans?
28
Are Enterprise JavaBeans and JavaBeans the same thing?
29
What is an enterprise bean?
30
How many development roles are involved in J2EE application?
31
What is Enterprise JavaBeans?
32
What's different in Enterprise JavaBeans 1.1?
33
When should I adopt BMP and when I should use CMP?
34
If my session bean with single method insert record into 2 entity beans, how can know that the process is done in same transaction (the attributes for these beans are Required)?
35
What is clustering?
36
How to implement an entity bean which the PrimaryKey is an auto numeric field?
37
Can a Session Bean be defined without ejbCreate() method?
38
If I throw a custom ApplicationException from a business method in Entity bean which is participating in a transaction, would the transaction be rolled back by container?
39
Static variables in EJB should not be relied upon as they may break in clusters. Why?
40
Why are ejbActivate() and ejbPassivate() included for stateless session bean even though they are never required as it is a no conversational bean?
41
Why an onMessage call in Message-driven bean is always a separate transaction?
42
Can I develop an Entity Bean without implementing the create() method in the home interface?
43
What is the need of Remote and Home interface. Why can't it be in one?
44
What is the advantage of putting an Entity Bean instance from the Ready State to Pooled State?
45
What is a Message Driven Bean, what functions does a message driven bean have and how do they work in collaboration with JMS?
46
For Entity Beans, What happens to an instance field not mapped to any persistent storage, when the bean is passivated?
47
How is persistence implemented in enterprise beans?
48
What is the difference between a Server, a Container, and a Connector?
49
Why do we have a remove method in both EJBHome and EJBObject?
50
Why is ejbFindByPrimaryKey mandatory?
51
Is there any default cache management system with Entity beans?
52
What is the difference between session and entity beans? When should I use one or the other?
53
What is the default transaction attribute for an EJB?
54
Is it possible to stop the execution of a method before completion in a SessionBean?
55
Is it legal to have static initializer blocks in EJB?
56
Is it possible for an EJB client to marshal an object of class java.lang.Class to an EJB?
57
What is an EJB Context?
58
What is the difference between Message Driven Beans and Stateless Session beans?
59
What happens if remove( ) is never invoked on a session bean?
60
What are the special design cares that must be taken when you work with local interfaces?
61
Brief description about local interfaces?
62
What is the advantage of using Entity bean for database operations, over directly using JDBC API to do database operations? When would I use one over the other?
63
Can you control when passivation occurs?
64
Can the primary key in the entity bean be a Java primitive type such as int?
65
The EJB container implements the EJBHome and EJBObject classes. For every request from a unique client, does the container create a separate instance of the generated EJBHome and EJBObject classes?
66
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?
67
How EJB Invocation happens?
68
What are Entity Bean and Session Bean?
69
What is message-driven bean?
70
What are the key benefits of the EJB technology?
71
What are the key features of the EJB technology?
72
What is session Facade?
73
What is EJB?