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iiop question

 
Alex sinna
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Hi,all
I have prepared the SCEA-I exam for some time,and I have some questions
concerning iiop ,ejb and iterator pattern as follows:
Questions on iiop:
1.Is the iiop connection based or not?
2.Does the iiop have the secure feature?
3.iiop is protocol,is it used in remote-object distributed programming?

Questions on ejb:
1.Does the all entity been and stateless bean rather than Stateful
bean whose all instances of been are same unless working with some
client?

Questions on iterator pattern :
1.In iterator pattern ,does it allow different iterators to access a
data collection simultaneously?
Thanks
 
Roop Kishore
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Dont be worried alex i have already cleared the j2ee exam 1. Design patterns will not be asked throughly. just have knowledge of 21 design patterns given in sun blueprint. Only 2 or 3 question will come. which i think any one can answer. you must stress on implementing security in j2ee application. Implementing Certificates. bye
 
Alex sinna
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Can you answer my question concretely?
 
Vishwa Kumba
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Originally posted by Alex sinna:
Questions on ejb:
1.Does the all entity been and stateless bean rather than Stateful
bean whose all instances of been are same unless working with some
client?
[/QB]

Can you explain this question more clearly?. I am not able to understand it.
 
Alex sinna
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I want to know whether all instances of entity bean are same unless working with some client? So does Stateless bean? So does Stateful bean ?
Thanks
 
Srinivas Bitla
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Hi,
Questions on iiop:
1.Is the iiop connection based or not?
Ans. Yes, IIOP is connection based. IIOP is connection-oriented unlike HTTP, where communication is performed in request-response model (open connection-send request-receive response-close connection). In IIOP virtual connection is maintained through the session, so there is no need to reestablish it over and over again with every new invokation.
2.Does the iiop have the secure feature?

Ans. I do not think that IIOP has secure feature. Unless SSL or encryption is used, the communication is not secure.
3.iiop is protocol,is it used in remote-object distributed programming?
Ans. This is obvious. It is used for distributed programming.
Questions on ejb:
1.Does the all entity been and stateless bean rather than Stateful
bean whose all instances of been are same unless working with some
client?
Ans. When entity beans and stateless session beans are not servicing a client, then they are in a pool of instances. In the pooled state all instances are considered identical. Another point about stateless session beans is that even if they are servicing a client, they are considered identical. This is because they do not hold any conversational state. So calling isIdentical on stateless session beans always return true even if they are servicing a client or in pooled state.
Questions on iterator pattern :
1.In iterator pattern ,does it allow different iterators to access a
data collection simultaneously?
Ans. No.
regards,
Srinivas.
 
Jay Kipler
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Originally posted by Srinivas Bitla:
Hi,
<snip/>
Questions on iterator pattern :
1.In iterator pattern ,does it allow different iterators to access a
data collection simultaneously?
Ans. No.
regards,
Srinivas.

Of course the answer is yes! The Gang of 4 book on Design Patterns explicitly mentions it: "You might also need to have more than one traversal pending on the same list". Why shouldn't it be allowed? You need it, for example, if you want to compare two collections.
 
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