[jboss-dev-forums] [Design of POJO Server] - Re: Zero turnaround Java/JBoss

[bill.burke@jboss.com]

anonymous wrote : Try this in eclipse. As soon as you make one single schema change to any class, HotSwap is hosed until you restart JBoss. Of course, this is totally crap, but that tells you how crap HotSwap is.

Again, I hope you realize that if HotSwap is not used, this requires a recycling of classloaders of the component as well as any classloaders of dependent components.  For instance, change an @Entity bean, and you have to cycle the classloader of EJBs that reference it, then the classloaders of the WARs that reference the EJBs (if you're using @Local).

anonymous wrote : (1) the ability to efficiently "redeploy", under the assumption that the metamodel has not changed. So the internal implementation of the components might have changed, but there is no reason to actually restart the EJB container and the webapp.
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I hope you realize that this isn't some cross-cutting functionality that you can just snap on.  Since classloaders have to be recycled, this means all affected containers (web, ejb, and hibernate) have to do some re-initialization.   For instance, the EJB container references tons of Class, Method and Field objects that will need to be recycled.  Maybe what we could do is write a parallel reflection hierarchy that just delegates to real reflection objects.  This reflection model could register itself with the classloader of the real reflection object.  The classloader could ask registered reflection objects to recycle themselves upon classloader recycling.  (Say that 5 times fast).

BTW, Each component type is going to need to be seriously refactored to support optimized redeployment.  (BTW, with my measurements with E-EJB3, Hibernate is the biggest hog at boottime).

What it boils down to is that there's TONS and TONS of work to do before we can even think about adding HTTP Session/ SFSB serialization (and I think this idea is just a toy anyways...)

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