What's the advantage of adding a "serialVersionUID" to a Java source file?

EJB Questions:
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Give some examples of services offered by a EJB container?. What's the advantage of component model of software design?

How does the EJB container manage to intercept calls to a remote object and apply transactions, security?

Can an Entity EJB be dedicated to a single client?

What protocol is used when a EJB client communicates with a EJB server?

What's the difference btw EJB and CORBA models?

What's the difference between JSP include directive and include element?

Struts Questions

-- Explain the Struts architecture.
-- What are form-beans. Why are they required. Heard of DynaActionForm? Are form-beans required in Struts2?
-- How is form validation done in Struts?
-- Is validation done on server side of client side or both? Javascript vs Java?
-- Can there be more than one struts-config file?.
-- Can I change the name of the struts config file?
-- Can I use Tiles, Velocity template engine with struts?

-- What is the use of custom tags in JSP?
-- Would U use JSTL or Struts custom tags in Ur JSP pages?
-- What does the TLD file contain?
-- Difference between Struts 1.x and Struts 2.x?
-- How to use the MDC/NDC in Log4J with Struts? Where to put in the code? Which common place?
-- Can Struts2 be used with JSF?
-- How is AJAX handled in Struts 2?
-- Can we use JQuery instead of DWR?
-- Tiles vs IFrame? Pros and cons..
-- Can a single webapplication have some resources to be accessed thru HTTP and some by HTTPS?