J2EE 试题(稚嫩)

更多精彩请到 http://www.139ya.com

整理资料竟然发现N年前出的一些J2EE的试题，比较稚嫩，呵呵

Single selection

1.:
True or false: an EJB implements its remote or local interface.

A) True
B) False

2. :
Which type of beans can not be activated/passivated?

A) Stateless Session Beans
B) Stateful Session Beans
C) CMP Entity Beans
D) BMP Entity Beans

3. :
True or false: EJB supports nested transactions.

A) True
B) False

4. :
True or false: An EJB2.0 CMP Entity Bean class is abstract?

A) True
B) False

5.:
Which one of the following items is not needed when writing an entity EJB:

A) A bean class
B) A primary key class
C) A persistence class
D) A home/local home interface
E) A remote/local interface

6. :
What considerations make sense when writing an entity bean?

A) Use CMP when storing standard datatypes and performance is essential
B) Use CMP when storing standard datatypes and performance is not essential
C) Use CMP when storing complex datatypes and performance is essential
D) Use CMP when storing complex datatypes and performance is not essential

7. :
What is the default port for IIOP?

A) 443
B) 535
C) 1099



8.:
How many subscribers can there be in a Point-to-Point messaging system?

A) 0
B) 1
C) n

9.:
True or false: ejbActivate is called before activation

A) True
B) False



10.:
Where is a stub located?

A) On the client
B) In between the client and the server
C) On the server



Answer:

1. False, the container does
2. A. Only stateful session beans and entity beans can be activated/passivated
3. False. For the moment, EJB doesn't support nested transactions
4. True, EJB1.1 is not abstract
5. C, An entity bean requires a (local)home interface, a remote/local, a bean class and a primary key class
6. B. CMP is good at storing standard datatypes, not complex ones. It's performance is not under control of the programmer, but depends heavily on the implementation of the persistence engine
7. B. The default port for IIOP is 535
8. C. A Point-to-Point messaging system can have many subscribers. However, a message will only be delivered to one subscriber, and removed from the queue afterwards.
9. False, When the EJB container activates an EJB instance, it gives you the opportunity to initialize things afterwards.
10. A. A stub is located on the client, it forms the port for the client to talk to the server