By throwing RestartResponseAtInterceptPageException an application can temporarily redirect to an intercept page and then continue to the original destination. This is very handy to show a login page if the user is not authorized, for example. Unfortunately, this only works for GET requests. The problem is that only the current request URL is remembered when the exception is thrown and a redirect to this url is issued later. If the intercepted request is a POST, any request parameters are forgotten.
The use case I have in mind is that we have a back end system which has it's own login token which we may lose at any time (for example, if the user logs in again using another tool). Assume that the user is trying to add a new item in a form in the web browser. The problem is that we need to use the back end system to process the submit of that form. It would be nice if we could just show the intercept page and then continue the original form submit.