The problem occurs for a variety of JSP expressions, but the one from
the stack trace is: <c:if test="${threadTool.player.moderator}">
threadTool is a ThreadTool object in the request scope. It has an
inheritance chain like this:
ThreadTool extends ForumTool extends Paged extends AuthRequired extends
TSOTool
The TSOTool class has this method:
/**
* Return information about the currently logged in player, or
null
* if nobody is logged in.
*/
public Player getPlayer()
{
return
(Player)this.getSession().getAttribute(KEY_PLAYER);
}
Perhaps the JSTL expression evaluator is having trouble with deep
inheritance chains? The case is simple enough... and it works 99% of
the time.
Thanks,
Jeff Schnitzer
[EMAIL PROTECTED]
The Sims Online
> -----Original Message-----
> From: Karr, David [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, February 13, 2003 8:29 AM
> To: Tag Libraries Users List
> Subject: RE: JSTL problems on Tomcat 4.1.x
>
> It might be useful if we could see your JSP code, and any relevant
bean
> code if it's non-trivial.
>
> -----Original Message-----
> From: Schnitzer, Jeff [mailto:[EMAIL PROTECTED]]
> Sent: Wed 02/12/2003 3:17 PM
> To: [EMAIL PROTECTED]
> Cc:
> Subject: JSTL problems on Tomcat 4.1.x
>
>
>
> I get an occasional NullPointerException deep in JSTL when
running
> under
> load on Tomcat 4.1.x. This doesn't occur under 4.0.x. Are the
JSTL
> tags tested on Tomcat 4.1.x?
>
> When this problem happens, the page half-loads (up to the tag
that
> fails). Refreshing the page almost always works fine. Under
heavy
> load, maybe 1 in 100 page executions cause this problem.
>
> Here is the deepest stack trace I have managed to obtain (by
> modifying
> the Jakarta taglibs slightly to print a little extra debugging):
>
> 2003-02-12 23:11:48,190 ERROR [STDERR] An error occurred while
> getting
> property "player" from an instance of class
> com.maxis.tso.community.tool.ThreadTool:
> java.lang.NullPointerException
> 2003-02-12 23:11:48,192 ERROR [STDERR] at
>
org.apache.taglibs.standard.lang.jstl.Logger.logError(Logger.java:96
> 5)
> 2003-02-12 23:11:48,192 ERROR [STDERR] at
>
org.apache.taglibs.standard.lang.jstl.Logger.logError(Logger.java:11
> 73)
> 2003-02-12 23:11:48,192 ERROR [STDERR] at
>
org.apache.taglibs.standard.lang.jstl.ArraySuffix.evaluate(ArraySuff
> ix.j
> ava:321)
> 2003-02-12 23:11:48,192 ERROR [STDERR] at
>
org.apache.taglibs.standard.lang.jstl.ComplexValue.evaluate(ComplexV
> alue
> .java:146)
> 2003-02-12 23:11:48,192 ERROR [STDERR] at
>
org.apache.taglibs.standard.lang.jstl.ELEvaluator.evaluate(ELEvaluat
> or.j
> ava:242)
> 2003-02-12 23:11:48,193 ERROR [STDERR] at
>
org.apache.taglibs.standard.lang.jstl.ELEvaluator.evaluate(ELEvaluat
> or.j
> ava:201)
> 2003-02-12 23:11:48,193 ERROR [STDERR] at
>
org.apache.taglibs.standard.lang.jstl.Evaluator.evaluate(Evaluator.j
> ava:
> 138)
> 2003-02-12 23:11:48,193 ERROR [STDERR] at
>
org.apache.taglibs.standard.lang.jstl.Evaluator.evaluate(Evaluator.j
> ava:
> 167)
> 2003-02-12 23:11:48,193 ERROR [STDERR] at
>
org.apache.taglibs.standard.lang.support.ExpressionEvaluatorManager.
> eval
> uate(ExpressionEvaluatorManager.java:112)
> 2003-02-12 23:11:48,193 ERROR [STDERR] at
>
org.apache.taglibs.standard.tag.el.core.IfTag.condition(IfTag.java:9
> 5)
> 2003-02-12 23:11:48,193 ERROR [STDERR] at
>
javax.servlet.jsp.jstl.core.ConditionalTagSupport.doStartTag(Conditi
> onal
> TagSupport.java:122)
> 2003-02-12 23:11:48,193 ERROR [STDERR] at
>
org.apache.jsp.mb_posts_jsp._jspx_meth_c_if_4(mb_posts_jsp.java:3923
> )
> 2003-02-12 23:11:48,194 ERROR [STDERR] at
>
org.apache.jsp.mb_posts_jsp._jspx_meth_c_if_3(mb_posts_jsp.java:3535
> )
> 2003-02-12 23:11:48,194 ERROR [STDERR] at
> org.apache.jsp.mb_posts_jsp._jspService(mb_posts_jsp.java:615)
> 2003-02-12 23:11:48,194 ERROR [STDERR] at
>
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:136)
> 2003-02-12 23:11:48,194 ERROR [STDERR] at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
> 2003-02-12 23:11:48,194 ERROR [STDERR] at
>
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrappe
> r.ja
> va:204)
> 2003-02-12 23:11:48,194 ERROR [STDERR] at
>
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:
> 289)
> 2003-02-12 23:11:48,194 ERROR [STDERR] at
>
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:240)
> 2003-02-12 23:11:48,194 ERROR [STDERR] at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
>
>
> Does anyone have any idea what is happening?
>
> Thanks in advance,
> Jeff Schnitzer
> [EMAIL PROTECTED]
> The Sims Online
>
>
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