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Some doubts

 
Pradeep bhatt
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I have copied the following from EJB spec, What is new in ejb 2.0
To support more efficient vendor implementations leveraging lazy loading and dirty detection mechanisms; to reduce memory footprints; to avoid data aliasing problems;etc.

1. What is dirty detection mechanism?
2. What does it mean " to reduce memory footprints"?
3. what is data aliasing?
 
Chris Mathews
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Originally posted by Pradeep Bhat:
1. What is dirty detection mechanism?

Dirty detection, in the context of EJB, is the ability to detect changes to an Entity Bean's state. The benefit here is, if no changes have taken place then there is no need for the Container to write the Entity Bean's state back to the database. In more advanced CMP implementations, the Container will actually detect which individual fields have changed and only write those fields instead of the whole whooping Entity.
Originally posted by Pradeep Bhat:
2. What does it mean " to reduce memory footprints"?

I think this one is pretty self-explanatory. The goal is to reduce the overhead, in terms of memory and performance, of the EJB Container.
Originally posted by Pradeep Bhat:
3. what is data aliasing?

Data-aliasing happens when two or more object hold references to the same object. This was very common in EJB 1.1 when using dependent objects (a best practice at the time). Data-aliasing contention was created when two or more entities referenced the same dependent object. The need for dependent objects has been removed in EJB 2.0 by introducing local interfaces.
 
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