Term
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Definition
| A technology that helps manage the server-side component architecture. |
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Term
What are the different types of EJBs?
(Hint: 3) |
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Definition
| Session Bean, Entity Bean, & Message Driven Bean. |
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Term
| What are Session Beans in EJBs? |
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Definition
| An extension of the client's application that deals with business logic. |
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Term
| What are Entity Beans in EJB? |
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Definition
| An ORM for EJBs, concerned with Data Access Logic. |
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Term
| What are Message Driven Beans? |
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Definition
| An enterprise bean that allows applications to process messages asynchorously. |
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Term
What are the advantages of using EJBs?
(Hint: 5) |
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Definition
- May be accessed by a variety of clients.
- Can be accessed remotely.
- Are supported by a rich set of services.
- Makes it easier to build Business components.
- Provides reliability, robustness, scalability. |
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Term
What interface must be supplied to a client in order to access a Session bean in EJB?
(Hint: 2) |
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Definition
The Remote Home Interface and the Remote Interface. |
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Term
How would you make an interface Remote?
(Hint: 3) |
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Definition
- extend java.rmi.Remote
- Each method must throw RemoteException
- Arguments and return types must be shippable.
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Term
Can Stateless Session Beans have multiple create() methods in Home Interface? |
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Definition
| No, it must have one create() with no arguements. |
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Term
Can Stateful Session Beans have multiple create() methods in the Remote Home Interface? |
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Definition
Yes, they can have overloaded create() methods, and do not need to have a no-arg create(). |
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Term
What is the difference between Stateless and Stateful Session Beans? |
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Definition
- A stateful bean remembers the client.
- A stateless bean forgets the client each time. |
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Term
What is a Remote Interface? |
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Definition
| Exposes the methods of the bean outside the container. |
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Term
What is a Remote Home Interface? |
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Definition
| It defines the bean's life-cycle methods which can be accessed outside the EJB container. |
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Term
What is a Local interface in EJB?
(Hint: not Remote) |
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Definition
| It defines methods that can be used by other beans in the same EJB container. |
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Term
What is a Local Home interface? |
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Definition
| It defines the life-cycle methods that can be used by other beans in the same EJB container. |
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Term
What is a Bean class in EJB? |
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Definition
| The session or entity bean classes that implement the bean's business and life-cycle methods. |
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Term
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Definition
| An object that implements the remote and/or local interfaces of the EJB on the server side. |
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Term
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Definition
| It manages the bean's life-cycle and is responsible for locating, creating and removing enterprise beans. |
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Term
What data types can be passed as parameters or returned from EJBs?
(Hint: 3) |
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Definition
Primitives, Serializable types, RMI remote types |
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Term
What are the types of message models for MDBs?
(Hint: 2) |
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Definition
- Queue (Point-to-Point) behaves like a first-in-first-out (FIFO) queue.
- Topic (Publish-and-Subscribe) all MDBs in the pool get the message simultaneously. |
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Term
Are the parameters of methods defined in EJB Remote interface passed by value or passed by reference?
(Hint: 2) |
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Definition
- Serializable objects are passed by value.
- Objects that implement java.rmi.Remote are passed as remote references. |
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Term
What is the difference between Local and Distributed transactions in EJB? |
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Definition
- Local transaction has only one Resource Manager.
- Distributed transactions spans multiple resources that participate in one unified transaction. |
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Term
How did you manage transactions in EJBs?
(Hint: 2) |
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Definition
By using CMT or BMT.
(Container-Managed Transaction or Bean-Managed Transaction)
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Term
What are the Transaction Attributes? (for CMT)
(Hint: 6) |
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Definition
| Required, Requires New, Mandatory, Never, Supports, Not Supported. |
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Term
What are the Transactional attributes support by MDBs?
(Hint: 2) |
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Definition
| Not Supported and Required. |
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Term
On what types of Exceptions will the container rollback the transaction in EJBs? |
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Definition
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Term
What API / Interface is used for BMT? |
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Definition
| javax.transaction.UserTransaction |
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Term
What do the Transaction Isolation Levels do? |
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Definition
When a transaction is performed, access is restricted for other transactions. |
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Term
What are the characteristics/properties of a Transaction?
(Hint: 4) |
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Definition
Atomic, Consistent, Isolated, Durable
(ACID) |
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Term
How do you manage security in EJB?
(Hint: 2) |
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Definition
- Programmatic (bean-managed): defined in the bean.
- Declarative (container-managed): defined in deployment descriptor. |
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Term
What does a BMT do in EJB?
(Bean-Managed Transaction) |
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Definition
| It allows you to explicitly state where the transaction starts, ends, commits, and rollsback. |
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Term
What does a CMT do?
(Container-Managed Transaction) |
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Definition
| The Container starts, commits, and rolls back a transaction on our behalf. The container must be told how to manage the transaction by using deployment descriptors or annotations |
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Term
| Identify each Transaction Isolation Level. |
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Definition
| Read Uncommitted, Read Committed, Repeatable Read, and Serializable. |
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Term
| What is the difference between authentication and authorization security in EJB? |
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Definition
- Authentication involves identifying who the caller of the EJB is.
- Authorization ensures only authenticated principals with right permission can access the components. |
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