void callback(HttpServletRequest req,
HttpServletResponse resp,
Map authnIdentifiers,
AuthenticationSourceKey authenticationSourceKey,   
AuthenticationSelectorContext authnSelectorContext); 
PingFederate calls the callback() method after a selected authentication source is authenticated against. The callback() method allows authentication selectors to update resulting attributes, set cookies, or perform other custom functions.

Writing content to the resp object in the callback() method is not supported, and doing so may result in unexpected behavior. Setting cookies is acceptable.