Use of $link.setForward('forward-name') will not find forward local forwards for the currently-executing action mapping.
For instance, if you have the following configuration:
<forward name="foo" path="/foo.jsp" />
<action path="/myAction" ...>
<forward name="foo" path="/bar.jsp" />
Using $link.setForward('foo') will result in "foo.jsp" instead of "bar.jsp". I believe that the latter is more in line with the spirit of Struts' forward hierarchy.