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concurrent access?

Forrest Xu
Ranch Hand

Joined: Nov 16, 2002
Posts: 92
Which of the following do NOT support concurrent access?
A. Stateful session beans
B. Stateless session beans
C. Entity beans
D. Message-driven beans
a and b,
right?
Forrest Xu
Ranch Hand

Joined: Nov 16, 2002
Posts: 92
Seems A,B,D. Only Entity beans supports concurrent access.
But why choose 2 answer?
rastin purr
Ranch Hand

Joined: Jul 20, 2002
Posts: 73
IMHO, any beans that supports reentrant to be set to true allows concurrent access.
Pradeep bhatt
Ranch Hand

Joined: Feb 27, 2002
Posts: 8919

Answers are
A. Stateful session beans
B. Stateless session beans


Groovy
rastin purr
Ranch Hand

Joined: Jul 20, 2002
Posts: 73
I think IMHO it should be ABD because all three Entity, Session and MDB does not support reentrant hence cannot be concurrently accessed.
regards
Pradeep bhatt
Ranch Hand

Joined: Feb 27, 2002
Posts: 8919

I think IMHO it should be ABD because all three Entity, Session and MDB does not support reentrant hence cannot be concurrently accessed.

Entity beans can be reentrant. IN MDB reentrant does not make sense because client cannot directly invoke the bean but the container does and container makes sure that no more than one request is made to a bean.
Dragan Milic
Ranch Hand

Joined: Oct 03, 2002
Posts: 31
Originally posted by Pradeep Bhat:

Entity beans can be reentrant. IN MDB reentrant does not make sense because client cannot directly invoke the bean but the container does and container makes sure that no more than one request is made to a bean.

Just a note on the SLSB: IMHO reentrant SLSB is an oxymoron, since the container can use only one SLSB per business method call.

Dragan
[ August 29, 2003: Message edited by: Dragan Milic ]
Pradeep bhatt
Ranch Hand

Joined: Feb 27, 2002
Posts: 8919

Dragan SLSB cannot be reentrant.
Dragan Milic
Ranch Hand

Joined: Oct 03, 2002
Posts: 31
Originally posted by Pradeep Bhat:
Dragan SLSB cannot be reentrant.

Hi,
as usually i did NOT read carefully the question (especially the NOT part of it ). So, forget what I said

Dragan
rastin purr
Ranch Hand

Joined: Jul 20, 2002
Posts: 73
Sorry, I mean to say SFSB, SLSB and MDB not entity bean. Just notice that

therefore, I think that (IMHO) the answer should be ABD
[ August 29, 2003: Message edited by: rastin purr ]
[ August 29, 2003: Message edited by: rastin purr ]
Pradeep bhatt
Ranch Hand

Joined: Feb 27, 2002
Posts: 8919

D is also the answer. MDB concurrently processes JMS messages but the does not allow concurrent access. The EJB container ensures that an MDB instance processes only one JMS message at a time.
[ September 02, 2003: Message edited by: Pradeep Bhat ]
Pradeep bhatt
Ranch Hand

Joined: Feb 27, 2002
Posts: 8919

I always monitor your posts!
Just kidding!
Originally posted by Dragan Milic:

Hi,
as usually i did NOT read carefully the question (especially the NOT part of it ). So, forget what I said

Dragan
Diana Finis
Greenhorn

Joined: Jan 27, 2003
Posts: 11
Regarding Entity beans: I understand that concurrent access is allowed to entity object, and not entity instance, right? So if we are talking about entity instance the answer includes C too? Is that right?
Thanks,


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