Убедитесь, что ваш web.xml настроен, как показано ниже. Рабочий пример здесь .
<servlet>
<servlet-name>appstats</servlet-name>
<servlet-class>com.google.appengine.tools.appstats.AppstatsServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>appstats</servlet-name>
<url-pattern>/appstats/*</url-pattern>
</servlet-mapping>
<filter>
<filter-name>appstats</filter-name>
<filter-class>com.google.appengine.tools.appstats.AppstatsFilter</filter-class>
<init-param>
<param-name>logMessage</param-name>
<param-value>Appstats available: /appstats/details?time={ID}</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>appstats</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<security-constraint>
<display-name>appstatsConstraint</display-name>
<web-resource-collection>
<web-resource-name>appstatsCollection</web-resource-name>
<url-pattern>/appstats/*</url-pattern>
</web-resource-collection>
<auth-constraint>
<role-name>admin</role-name>
</auth-constraint>
</security-constraint>