tomcat-taglibs-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Schnitzer, Jeff" <JSchnit...@maxis.com>
Subject RE: JSTL problems on Tomcat 4.1.x
Date Thu, 13 Feb 2003 20:38:39 GMT
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
jschnitzer@maxis.com
The Sims Online

> -----Original Message-----
> From: Karr, David [mailto:David.Karr@wamu.net]
> 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:JSchnitzer@maxis.com]
> 	Sent: Wed 02/12/2003 3:17 PM
> 	To: taglibs-user@jakarta.apache.org
> 	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
> 	jschnitzer@maxis.com
> 	The Sims Online
> 
>
--------------------------------------------------------------------
> -
> 	To unsubscribe, e-mail:
taglibs-user-unsubscribe@jakarta.apache.org
> 	For additional commands, e-mail: taglibs-user-
> help@jakarta.apache.org
> 
> 


---------------------------------------------------------------------
To unsubscribe, e-mail: taglibs-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: taglibs-user-help@jakarta.apache.org


Mime
View raw message