Is it an acceptable practice to use response.sendRedirect() in a JSP page? Or should you just throw an exception and use the error page directive?
A pageContext.forward() will "jump" to the url specified which may be a relative url like "other.jsp" to indicate it is in the same base location as the current page. The browser location box will show the URL of the original page, not the one you redirected to. There is no additional trip back to the browser and then back to the server so time is kept to a minimum.
When using pageContext.forward(), this forwards the original request and response objects. If you need to change one of the attributes in the original request object, there is no function to do this but this can be reset by passing new querystrings in the URL given to forward.
So the answer to your question, in no uncertain terms, is "maybe". It just depends on what you want to do.