jsp means very less code in java.and also their is no tags 
for intigrate with other logic.i.e means controll with 
other logic just like as connection polling,data accessing 
object,persistance logic.suppose u take as jsp as 
controller programmer feels lot of complexity.Hence 
industry recomended struts as controller.in servlet easy 
intigrate with other logic.
Industry recomended as MVC rule servlets as controller,jsp 
as view layer.

Controlling is a server side task and it makes no sense to
write you java code inside a jsp.