I got

javax.servlet.ServletException: Error instantiating servlet class servlets.MemoServlet
javax.naming.NameNotFoundException: Name servlets.MemoServlet is not bound in this Context

when using

<form action="MemoServlet">

I know I could use managedbeans, but I've to use servlets.

I suspect the problem has to do with JSF.

context.xml:

<?xml version="1.0" encoding="UTF-8"?>
<Context antiJARLocking="true" path="/MemoWeb/faces"/>

web.xml:

<servlet-mapping>
    <servlet-name>MemoServlet</servlet-name>
    <url-pattern>/faces/MemoServlet</url-pattern>
</servlet-mapping>

<servlet>
    <servlet-name>MemoServlet</servlet-name>
    <servlet-class>servlets.MemoServlet</servlet-class>
</servlet>

I seem to have this problem all over the place:

com.sun.faces.mgbean.ManagedBeanCreationException: An error occurred performing resource injection on managed bean userManager
....
Caused by: javax.naming.NameNotFoundException: Name user.UserManager is not bound in this Context