Can not directly call request.getParameterMap (). Size () do ?

Write request.getParameterMap ()

emergence of this phenomenon:
1 and 2 are not directly call request.getParameterMap (). size () to get the number of key-value pairs



can only be placed on a Map map = request.getParameterMap ()
then use map.size () to obtain

I ask why

------ Solution ------------------------------------ --------
I could write here
int size = request.getParameterMap (). size ();
------ For reference only ----------------- ----------------------

restart tomcat solved a bit baffling