Hi,

Add the following code in the web.xml file:

<error-page>
  <error-code>404</error-code>
  <location>/WEB-INF/views/notfound.jsp</location>
</error-page>

and in the servlet you can use the following code:

public void doGet(HttpServletRequest request, HttpServletResponse response) {
    response.sendError(HttpServletResponse.SC_NOT_FOUND);
}

Check more Servlet tutorials.

Thanks