Servlets and JSPs together are considered to be presentation layer components.... so treating servlets as application [i suppose what you were intending was business] components is incorrect in the first place.
Now if you have both your servlets and JSPs in one machine, [inside the web/app container ofcourse], you can have your business components in any other system [hosted as webservices or EJBs] and access them via
SOAP [for webservices] or RMI/IIOP [for EJBs].