Mohana Murali

Roger, Thanks for reply.

Somewhere in this forum, I read that, using JDNI lookup facilitates using container services. This might be true for EJB. How about JDBC DataSource lookup. Are we still getting some transaction management services from container? Or services comes with JDBC itself. Do we still have advantages of looking up through JNDI?

Thanks Nadeem, So it always SystemException(NoSuchEntityException).

Roger, I meant Correlation ID not connection ID, My question was incorrect. Does Correlation ID used for synchronous communication using JMS?

JNDI lookup helps to easy way to get resources hooked and loosely coupled.
Other than this is there any real advantages compared to other approches of JNDI lookup?

Thanks for the answers.

1) I am still not clear about it. I was asked in inteview about it. I do informed that, you can not delete record since it was locked by container. But they told me to assume that "record can be deleted from DB" and explain the consequences. I said, container throws SystemException. Is it not true? It looks like container can not able to find the row it is about to update just after transaction and not able to find it. So it's a irrecoverable system erorr?!!!

Well I got same question in another interview. I said, container throws ObjectNotFound exception, Thinking that it should be application exception and developer suppose to catch it in every entity bean. May be I was wrong in both answers.

So I am not sure which is the correct answere for it.

2) DD can be configured to make sure, MDB receives the expected message. Do we still need correction ID concept to be complete solution? if not when do we need correction IDs also?

This is just an extension to Paul message.

If bean is in Transaction, Container does not persist the bean or remove bean from pool, even you set timeout. Use web containter maintain the session invalidation to solve this problem.

Or you can keep the wait time in session bean, you can know when the session begins transaction by checking afterBegin() method of SessionSynchronization interface (In case of CMP only). Wait for certain time and roll back transaction EJBContext.setRollbackOnly().


In case of BMT you can roolback your tranasaction by explicitly calling rollback after certain time.

Using session management at webcontainer level is better stretegy.

Use Topic if you want to send message more than one destinations. Use Queue if you want to send message to one destination.

We should not choose Topic or Queue with respect to Cluster or non cluster.
If you use MQ and Queue type messaging. MQ admin can also control MQ clustering instead of application clustering. Same is true for Topic also. So do not bother much about clustering when you make decision about Queue or Topic. Go by requirement suitability.

Keep your text file in class path. Try reading from ClassLoader as stream.

Hi,

1)What happens to Entity bean if we running application and delete the row(whose entity bean is active) from backend database manuvally. Does Entity bean throw Object not found exception? Does Entity bean keep the state of Entity bean?


2)How does MDB know the incoming message is belong to it and consumes it? How does other MDB does not consume it. (Assume message type is same for all implemented MDBs).

I keep getting above interview questions, I am not sure I am right.

Thanks in advance,
Mohana

Sam,

here is good article on it. May be in will help more on understanding JMS transactions and acknowledgements.

http://www.javaworld.com/javaworld/jw-03-2002/jw-0315-jms_p.html

Mohana

I need to append two different images and make it one image.
Basically I have TIFF image one page1 and page2. I am using JAI to read two pages and convert them as two different images. Now I need to append those two images one below another and make as one single image. The format of image can TIFF/JPEG/PNG.
Hope This is the right forum for this query.

posted December 21, 2003 01:12 AM
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FYI:
Right click on the links below and click on "Save Target As.."
SCJP
http://www.geocities.com/ko_ko_9/SCJPNotes.zip
SCBCD
http://www.geocities.com/ko_ko_9/EJB2Notes.zip

"assert" works as keyword if it compiled with assertions, otherwise it is not a keyword.
I guess it will not be asked in exam while referring keywords due to ambiguty.

Hi,
I have emailed PPT notes to [email protected].
PPT it will be uploaded and URL will be informed in this thread soon.
Mohana

HI,
I have scbcd notes on PPT. If your interested to have them please let me know you email id.
I will upload to some site soon.
Mohana

Hi
I have sent SCJP notes to all the emails in this thread.
I have not sent SCBCD notes to these email ids.
If I miss anybody please let me know.
Mohana Murali Krishna