Thank God I passed SCWCD 5 today with a score of 92%. I would like to thank the Java community for their efforts and generosity in providing us with valuable resources to study. Special thanks to:
* Charles Lyons for his book "Sun Certified Web Component Developer Study Companion".
* Bryan Basham and et al for their book "Head First Servlets and JSP".
* JavaRanch website for the marvelous resources.
* The Java community in general.
I took the exam after solving many mock exams (around 12) and this helped me to reduce uncertainty and understand the tone of exam questions.
I still have two unanswered questions in my mind:
* Regarding session migration, who takes responsibility of keeping session info synchronized across multiple independent servers? Is it the load balancer? Or another entity?
* Does the business delegate code belong to the web component or the EJB component?
who takes responsibility of keeping session info synchronized across multiple independent servers
In a distributed environment the Session object is moved from one JVM to the other depending one where the Request is coming in. As there is only one Session Object there is no need of synchronizing (apart from synchronizing updates on the attributes contained in the Session object, but that does apply in a non-distributed environment as well).
Does the business delegate code belong to the web component or the EJB component?
The Business delegate hides the way the underlying business service is implemented, so the service might also be implemented by something other than EJB's. Therefore it is not part of the EJB component, but it is positioned in the Business Layer (not in the Presentation Layer).