Symptoms:
Any JSP pages in the project produce error messages as below:
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: 5 in the jsp file: /check.jspf
Generated servlet error:
*Duplicate local variable usr*
An error occurred at line: 5 in the jsp file: /check.jspf
Generated servlet error:
*Duplicate local variable path*
An error occurred at line: 5 in the jsp file: /check.jspf
Generated servlet error:
*Duplicate local variable pos*
An error occurred at line: 5 in the jsp file: /check.jspf
Generated servlet error:
*Duplicate local variable hSession*
An error occurred at line: 5 in the jsp file: /check.jspf
Generated servlet error:
*Duplicate local variable testRegister*
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:512)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
    com.byinsight.logic.EncodingFilter.doFilter(EncodingFilter.java:22)
Ddevelopment environment:
- JDK 1.5
- Tomcat 5.0
- IDE Eclipse 3.3
Reasons:
I was using jsp-config to include a JSPF in every JSP file. The web.xml is below:
<jsp-config>
    <jsp-property-group>
        <url-pattern>*.jsp</url-pattern>
        <include-prelude>/check.jspf</include-prelude>
    </jsp-property-group>
</jsp-config>
The included file is check.jspf. The code in JSPF is below:
<%@page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@page import="com.byinsight.model.User"%>
<%@page import="javax.servlet.http.HttpSession"%>
<%
    //String str = (String)session.getAttribute("login");
    User usr = (User)session.getAttribute("user");
    String path = request.getServletPath();
    int pos = path.indexOf("index.jsp");
    HttpSession hSession = request.getSession(false);
    String testRegister = (String)hSession.getAttribute("register");
    if (-1 == pos) {
        if ((null == usr) && (!testRegister.equals("login"))) {
            throw new RuntimeException("you have to login first ");
        }           
    }
%>
The project runs well in Eclipse, but when I deploy the WAR into product system, the error displays. I do not understand what does the error message means, the are no duplicate variables here! Somebody knows? Thank you very much!
 
     
     
    