Error: NOT_FOUND <---> Google Apps Eng

Question

I'm working on a GAE. when I try it in local it works fine. But, When I deploy it, it shows me Error: NOT_FOUND... I don't know what's really going on. Can someone help me. Thank u. U can check the web.xml which is set like this:

<?xml version="1.0" encoding="utf-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

    <filter>
        <filter-name>UserFilter</filter-name>
        <filter-class>com.link.UserFilter</filter-class>
    </filter>
    <filter>
        <filter-name>AdminFilter</filter-name>
        <filter-class>com.link.AdminFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>UserFilter</filter-name>
        <url-pattern>/user/*</url-pattern>
    </filter-mapping>
    <filter-mapping>
        <filter-name>AdminFilter</filter-name>
        <url-pattern>/admin/*</url-pattern>
    </filter-mapping>
    <servlet>
        <servlet-name>BuyServlet</servlet-name>
        <servlet-class>com.link.BuyServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>BuyPaypalServlet</servlet-name>
        <servlet-class>com.link.BuyPaypalServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>LogoutServlet</servlet-name>
        <servlet-class>com.link.LogoutServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>AddUserServlet</servlet-name>
        <servlet-class>com.link.AddUserServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>DropUserServlet</servlet-name>
        <servlet-class>com.link.DropUserServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>ModifyUserServlet</servlet-name>
        <servlet-class>com.link.ModifyUserServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>ParameterServlet</servlet-name>
        <servlet-class>com.link.ParameterServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>PaypalServlet</servlet-name>
        <servlet-class>com.paypalX.AdaptiveFnAPIServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>BuyServlet</servlet-name>
        <url-pattern>/user/buy</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>BuyPaypalServlet</servlet-name>
        <url-pattern>/user/buypaypal</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>LogoutServlet</servlet-name>
        <url-pattern>/logout</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>AddUserServlet</servlet-name>
        <url-pattern>/admin/adduser</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>DropUserServlet</servlet-name>
        <url-pattern>/admin/dropuser</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>ModifyUserServlet</servlet-name>
        <url-pattern>/admin/modifyuser</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>ParameterServlet</servlet-name>
        <url-pattern>/admin/setparameter</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>PaypalServlet</servlet-name>
        <url-pattern>/processPayment</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>30</session-timeout>
    </session-config>
</web-app>

Answer 1

Your app is configured to redirect requests for / to /user/index.jsp, but you don't appear to have a handler mapped for that URL. Beyond that, it's impossible to say anything useful without seeing your code.