Hi john, This is from a search result i did on google for your question:
public RequestDispatcher getRequestDispatcher(java.lang.String path)Returns a RequestDispatcher object that acts as a wrapper for the resource located at the given path. A RequestDispatcher object can be used to forward a request to the resource or to include the resource in a response. The resource can be dynamic or static. The pathname specified may be relative, although it cannot extend outside the current servlet context. If the path begins with a "/" it is interpreted as relative to the current context root. This method returns null if the servlet container cannot return a RequestDispatcher.
The difference between this method and ServletContext.getRequestDispatcher(java.lang.String) is that this method can take a relative path.
What this means is that with the ServletContext's RequestDispatcher, the path is always set to the root of the context , ie '/' as compared to the Request's RequestDispatcher where you could specify a path relative to the resource servicing that request.
A simple example
Assume the resource that's servicing the current request is servlet/FirstServlet
Assume, i need to get to a resource /servlet/someOtherServlet using a request disptacher.