IMHO, Servlets should be only used as dispatch/processing modules (ie. posting to or some other specialized task).
JSPs should be used for presentation.
This argument is made because clients I've worked with don't necessarily agree with my web-designers and they work out the kinks. I don't want a web-designer mucking around in my servlet code, it's harder to totally ruin a JSP page. If they do, it's their fault haha
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