well in fact i have found a begun of solution but not the entire one.

it seems that the way to call a servlet is :
(in a <FORM ACTION="..." METHOD="POST"> or by entering the path in the navigator)
(as it is written in IBM red books Servlet and JSP programming)

if i put something else the navigator answer "page not found" and if i use
the path "/servlet/name_of_the_class" (in my case "/servlet/ShowParameters"
) , the server answer something like :

" ERROR 500
An error has occured while processing
Message:Server caught unhandled exception from servlet[invoker]
Target Servlet: invoker

Root Error-1: ShowParameters
java.lang.ClassNotFoundException: ShowParameters at .....

Wrapped Error-2: Servlet [ShowParameters]: Could not find required servlet
class -
javax.servlet.ServletException: Servlet [ShowParameters]: Could not find

required servlet class - ShowParameters.class at ...."

and if i call an other servlet - that is on the same directory than the
one i tested above - in the browser with the same way
("/websphere/servlet/servlet_that_works")it works !!

Both servlet (the one that works and the one that not) are in the same directory,
are both .class and are both called with the same method. but only one of
them function.

this thing is getting me mad.
if you have any idea please tell me, i gonna search by my own too as always
even if I'm really lost

Best regards ,