Why business logic written using servlets not in jsp?

Answer 1

It is usually done for two reasons:

1. For security purposes - No one can see the code inside a servlet but much of the code inside a JSP can be found out by right clicking on the web page and doing a "View Source"

2. There are only one or two Servlets in any application but there may be dozens of JSP's. if you code the business logic in a JSP, then you would have to replicate the same in all the JSP's where you want this feature. Instead if you place this logic inside the servlet, it is easier for re-use. Instead of copy pasting the code in multiple places, you can place the contents in one single place.