Re: NullPointer on getParameter

[Laurie Harper <zo...@holoweb.net>]

So to wrap this one up, the problem turned out to be a tag that wasn't 
resetting its state correctly -- or rather, was only doing so in its 
reset() method. All was fine with tag pooling turned off but with it on 
the tag could wind up with inconsistent internal state. Cleaning up in 
doEndTag() solved the problem. [I've added a note to that affect on bug 
21611 as well.]

L.

Laurie Harper wrote:
> Sure, I'll update Bug# 21611 as I get more details.
> 
> L.
> 
> Bill Barker wrote:
> 
>> I just got a ton of these while doing a stress-test to try and get 
>> another
>> bug to crawl out from under it's rock ;-).  I believe that there is a bug
>> here somewhere, but I'm currently chasing bug #1.  If your server logs 
>> are
>> more interesting than mine (which don't say much more than NPE at ...),
>> could you at least post them as an attachment to a bugzilla report?
>>
>> "Laurie Harper" <zo...@holoweb.net> wrote in message
>> news:bjo59g$nke$1@sea.gmane.org...
>>
>>> Agreed :-) But understanding the life cycle of CoyoteRequestFacade may
>>> make it easier to do so. There's nothing particularly funky going on in
>>> the code that's exhibiting the problem so I don't know yet what I can
>>> pare away. I'm trying to get a local build of Tomcat set up so I can add
>>> some tracing and narrow things down.
>>>
>>> L.
>>>
>>> Shapira, Yoav wrote:
>>>
>>>
>>>> Howdy,
>>>> The best thing is to come up with a way for us to reproduce it.  The
>>>> simplest, most direct way to get the exception.
>>>>
>>>> Yoav Shapira
>>>> Millennium ChemInformatics
>>>>
>>>>
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: Laurie Harper [mailto:zodiac@holoweb.net]
>>>>> Sent: Tuesday, September 09, 2003 6:17 PM
>>>>> To: tomcat-user@jakarta.apache.org
>>>>> Subject: NullPointer on getParameter
>>>>>
>>>>> Hi, I'm trying to figure out a problem we've encountered since
>>>>
>>>>
>>>> upgrading
>>>>
>>>>
>>>>> to Tomcat 4.1. I've seen this both on 4.1.24 and 4.1.27. I haven't yet
>>>>> reduced it to a specific recipe for reproduction outside the 
>>>>> context of
>>>>> my application but I do see this quite frequently so I thought I'd see
>>>>> if anyone else has come across it...
>>>>>
>>>>> The problem is that a call to getParameter is getting a
>>>>> NullPointerException in the delegation method on CoyoteRequestFacade:
>>>>>
>>>>> Caused by:
>>>>> java.lang.NullPointerException
>>>>>       at org.apache.coyote.tomcat4.CoyoteRequestFacade.
>>>>> getParameter(CoyoteRequestFacade.java:178)
>>>>>       at javax.servlet.ServletRequestWrapper.
>>>>> getParameter(ServletRequestWrapper.java:203)
>>>>>
>>>>> I checked the code and line 178 just a call to the wrapped
>>>>
>>>>
>>>> CoyoteRequest
>>>>
>>>>
>>>>> object, meaning that reference is null. Now, there's only two ways it
>>>>> could be null: a null reference was passed into CoyoteRequestFacade's
>>>>> constructor, or CoyoteRequestFacade.clear() was called.
>>>>>
>>>>> As I understand it, a CoyoteRequestFacade should be associated with a
>>>>> request when it starts and not released until the request has 
>>>>> completed
>>>>> so I'm leaning towards looking at the first possibility. Can anyone
>>>>
>>>>
>>>> give
>>>>
>>>>
>>>>> me an overview of the 'life cycle' of CoyoteRequestFacade? Where is it
>>>>> created, managed, assigned/reclaimed from a particular request, etc?
>>>>>
>>>>> Better yet, has anyone run into this and found a solution? The nearest
>>>>> thing I could find was Bug# 21611 which sounds like the same problem.
>>>>
>>>>
>>>>> From the commentary, it doesn't look like there's a known cause yet;
>>>>
>>>>
>>>>> what would be the best way to track this down (as I say, I can
>>>>
>>>>
>>>> reproduce
>>>>
>>>>
>>>>> the behaviour easily here)?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> L.
>>>>>
>>>>>
>>>>>
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>>>>
>>>>
>>>>
>>>>
>>>>
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