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HTTP Status 500 - error running servlet with JSP

 
Chandan Ghosh
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Posts: 2
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I'm attempting to run the program from chapter 3 of Head First Servlets & JSP, and I get the following error.I am using apache-tomcat-5.5.17, jdk1.6.0, jre1.6.0



HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
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.example.web.BeerSelect.doPost(BeerSelect.java:34)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

java.lang.NullPointerException
org.apache.jsp.result_jsp._jspService(result_jsp.java:51)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
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.example.web.BeerSelect.doPost(BeerSelect.java:34)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)


my servlet and jsp codes are like this:

result.jsp:
-----------


BeerSelect.jsp:
---------------


please someone help me debug this problem.



[BSouther: Added UBB CODE tags]
[ February 03, 2008: Message edited by: Ben Souther ]
 
Tom Katz
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Without seeing the BeerExpert code, or what line is throwing the NPE in the .jsp, my best guess is that there is a null List being returned so the JSP throws the null pointer exception.

I would debug/print-out the contents of that List before you set it as a request attribute.

Tom
 
Ben Souther
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You're setting an attribute named "sytles" but looking for an attribute named "styles" in your JSP.

Fix the typo and see if the problem goes away.
 
Tom Katz
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Doh! missed that typo . . .
 
Chandan Ghosh
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It was indeed typo mistake...thank you all
 
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