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Answer 1

+1 A:

response.setStatus(((Integer)request.getAttribute("javax.servlet.error.status_code")).intValue());

this line is causing the problem. comment it out and try outputting the value of request.getAttribute("javax.servlet.error.status_code") (without casting or intValue())

It is perhaps null

javax.servlet.error.status_code is only set if there has been an error. So if you are redirecting to the exception.jsp yourself, and not using it as an error-page, then there is no status code set, and hence - the NullPointerException

Bozho 2010-01-15 21:07:46

what made you downvote it? What have I missed / written wrong?

Bozho 2010-01-15 21:24:35

while that's correct, he has only identified the line (by the stacktrace), not the fact that this part of the row returns null. And I'm sure you've noticed that NPE is not always well understood.

Bozho 2010-01-15 21:41:15

Answer 2

+1 A:

Is that jsp page set as error page?

<web-app>
<!-- ..... -->
<error-page>
    <error-code>
        404
    </error-code>
    <location>
        /404.html
    </location>
</error-page>
<error-page>
    <exception-type>
        javax.servlet.ServletException
    </exception-type>
    <location>
        /servlet/ErrorDisplay
    </location>
</error-page>
<!-- ..... -->

A servlet in the for an rule could receive the following three attributes:

* javax.servlet.error.status_code : An Integer telling the error status code, if any
* javax.servlet.error.exception_type : A Class instance indicating the type of exception that caused the error, if any
* javax.servlet.error.message : A String telling the exception message, passed to the exception constructor

Teja Kantamneni 2010-01-15 21:18:53

Answer 3

+2 A:

With GlassFish, the line:

response.setStatus(((Integer)request.getAttribute("javax.servlet.error.status_code")).intValue());

is automatically generated by the JSP compiler for any JSP that has:

<%@page isErrorPage="true"%>

Here, for an unknown reason, the "javax.servlet.error.status_code" request attribute is not set or lost during the redirect so using <%@page isErrorPage="true"%> results in the NPE. This may be a bug in your code, in GlassFish, or in Sping (or not at all), but it is impossible to say without more details on your page flow, on your code.

There is a discussion in this thread about a very similar problem (similar, not identical, the root cause is not the same IMO) though. The suggested workaround is to not use the isErrorPage directive and to use the following EL code to access the error information:

${pageContext.errorData.throwable}
${pageContext.errorData.statusCode}
${pageContext.errorData.requestURI}
${pageContext.errorData.servletName}

As I said, I can't say if this is a bug in GlassFish, in Spring, or not a bug at all. But maybe open a ticket in GlassFish issue tracking system anyway. You may get a more precise answer (and help the community).

Pascal Thivent 2010-01-15 22:20:52

While technically this wasn't the "answer" to my problem, this answer did provide the background to better understand how I might troubleshoot my issue. This, coupled with the above idea to turn my logging to 'debug' led me to find the bug in my Java code that was causing this.

TimmyJ 2010-01-19 14:25:59

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