There seem to be least three issues
Classes are searched in
WEB-INF/classes rather than in
HttpServlet instead of the generic
doXXX methods of the
HttpServlet and not the generic
service method. The
service method dispatches to the corresponding
It seems you are trying to access the "showNewForm()" method through the URL "http://localhost:8081/Atelier1/listarticleclient/new", but the servlet mapping is set to "/client" in the web.xml file.
To call the method correctly, change the URL to "http://localhost:8081/Atelier1/client/new".
This should resolve the error.