It looks like the exception appears only when "maxLoadedJsps" and "
jspIdleTimeout" are set to a value >0 in tomcat/conf/web.xml and ".tag" files
are used with jsp- scriptlets.
Web.xml changes:
<init-param>
<param-name>maxLoadedJsps</param-name>
<param-value>1000</param-value>
</init-param>
<init-param>
<param-name>jspIdleTimeout</param-name>
<param-value>5</param-value>
</init-param>
The exception can be observed in the example "Tag Files" -> "Display Products
Example" but you have to edit the WEB-INF/tags/displayProducts.tag and append
the following example scriptlet:
<%
String test = "this is =";
if (normalPrice != null)
test = test + normalPrice + " something";
else
test = test + onSale + "=";
StringBuilder tags=new StringBuilder(test);
tags.append(".").append(test).append("..."); // change here
test = tags.toString();
request.setAttribute("test", test);
%>
<%=test %>
Start Tomcat and invoke the example jsp
http://localhost:8080/examples/jsp/jsp2/tagfiles/products.jsp
Wait and observe the catalina.out (or tomcat output) for exceptions. Normaly
the exception won't appear. Now edit the previously added scriplet in
WEB-INF/tags/displayProducts.tag modifying any string in one of the append
statements.
Call the example jsp again, tomcat should recompile the tag, wait and observe
again your tomcat output.
Do not shutdown or restart tomcat between these steps! Tomcat should recompile
the tag on the fly.
We were able to reproduce the exception on Tomcat 7.0.30, 7.0.32 and 7.0.33 on
different machines using the described steps.
Best regads
Laszlo
-----Ursprüngliche Nachricht-----
Von: Keszthelyi Laszlo [mailto:[email protected]]
Gesendet: Freitag, 07. Dezember 2012 15:10
An: Tomcat Users List
Betreff: AW: Tomcat 7: JSP unloading - NullPointerException
Thank you for your fast reply, i will try to reproduce the problem with the
example tag-files. Otherwise i will prepare a small web app to reproduce the
bug and post it.
Best regards,
Laszlo
-----Ursprüngliche Nachricht-----
Von: Konstantin Kolinko [mailto:[email protected]]
Gesendet: Freitag, 07. Dezember 2012 14:49
An: Tomcat Users List
Betreff: Re: Tomcat 7: JSP unloading - NullPointerException
2012/12/7 Keszthelyi Laszlo <[email protected]>:
>
> since Tomcat 7.0.30 (currently using version 7.0.33) I'm faced with the
> following NullPointerException:
>
> Dec 7, 2012 2:10:28 PM
> org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor
> processChildren
> SEVERE: Exception invoking periodic operation:
> java.lang.NullPointerException
> at
> org.apache.jasper.util.FastRemovalDequeue$Entry.access$700(FastRemovalDe
> queue.java:254)
> at
> org.apache.jasper.util.FastRemovalDequeue.remove(FastRemovalDequeue.java
> :177)
> at
> org.apache.jasper.compiler.JspRuntimeContext.checkUnload(JspRuntimeConte
> xt.java:610)
> at
> org.apache.jasper.servlet.JspServlet.periodicEvent(JspServlet.java:360)
> at
> org.apache.catalina.core.StandardWrapper.backgroundProcess(StandardWrapp
> er.java:709)
> at
> org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.proc
> essChildren(ContainerBase.java:1530)
> at
> org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.proc
> essChildren(ContainerBase.java:1540)
> at
> org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.proc
> essChildren(ContainerBase.java:1540)
> at
> org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.proc
> essChildren(ContainerBase.java:1540)
> at
> org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(
> ContainerBase.java:1519)
> at java.lang.Thread.run(Thread.java:662)
>
> I was able to debug and trace the exception and found that the Excpetion
> is caused by a '.tag', I'm including in my JSP, which has no
> UnloadHandle assigned when processed in
> org.apache.jasper.compiler.JspRuntimeContext.checkUnload() line 610:
> jspQueue.remove(jsw.getUnloadHandle());
>
> Because jsw.getUnloadHandle() returns null, jspQueue.remove() fails and
> is throwing the NullPointerException everytime, aborting the "unload".
>
> Does anyone have an idea how to solve this problem or is there already a
> fix?
>
Steps to reproduce = ?
Can you prepare a sample simple web application that demonstrates the
bug and file it into Bugzilla?
(Maybe it can be observed with the examples webapp? There are several
tags there.)
Best regards,
Konstantin Kolinko
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