Struts unload() causes NPE

[randahl]

Using JBoss 3.2.5 and struts 1.1 I keep getting exceptions when the destroy method of Struts' action servlet is invoked. I did not experience this on earlier versions of JBoss even though I had the same configuration as now.

Has anyone else experienced this? Below is my stack trace.

Randahl


16:14:22,953 ERROR [Engine] StandardContext[]Servlet action threw unload() excep
tion
javax.servlet.ServletException: Servlet.destroy() for servlet action threw excep
tion
at org.apache.catalina.core.StandardWrapper.unload(StandardWrapper.java:
1258)
at org.apache.catalina.core.StandardWrapper.stop(StandardWrapper.java:15
70)
at org.apache.catalina.core.ContainerBase.removeChild(ContainerBase.java
:952)
at org.apache.catalina.core.StandardContext.removeChild(StandardContext.
java:3126)
at org.apache.catalina.startup.ContextConfig.stop(ContextConfig.java:676
)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfi
g.java:218)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(Lifecycl
eSupport.java:119)
at org.apache.catalina.core.StandardContext.stop(StandardContext.java:44
87)
at org.apache.catalina.core.ContainerBase.destroy(ContainerBase.java:121
3)
at org.apache.catalina.core.StandardContext.destroy(StandardContext.java
:4573)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:582)
at org.apache.commons.modeler.BaseModelMBean.invoke(BaseModelMBean.java:
503)
at org.jboss.mx.server.RawDynamicInvoker.invoke(RawDynamicInvoker.java:1
09)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:473)
at org.jboss.web.tomcat.tc5.TomcatDeployer.performDeployInternal(TomcatD
eployer.java:142)
at org.jboss.web.tomcat.tc5.TomcatDeployer.performDeploy(TomcatDeployer.
java:70)
at org.jboss.web.AbstractWebDeployer.start(AbstractWebDeployer.java:306)

at org.jboss.web.WebModule.startModule(WebModule.java:62)
at org.jboss.web.WebModule.startService(WebModule.java:40)
at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanS
upport.java:271)
at org.jboss.system.ServiceMBeanSupport.jbossInternalLifecycle(ServiceMB
eanSupport.java:221)
at sun.reflect.GeneratedMethodAccessor73.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:582)
at org.jboss.mx.server.ReflectedDispatcher.dispatch(ReflectedDispatcher.
java:60)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:61)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:53)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.
java:185)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:473)
at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceControl
ler.java:837)
at $Proxy17.start(Unknown Source)
at org.jboss.system.ServiceController.start(ServiceController.java:367)
at sun.reflect.GeneratedMethodAccessor5.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:582)
at org.jboss.mx.server.ReflectedDispatcher.dispatch(ReflectedDispatcher.
java:60)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:61)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:53)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.
java:185)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:473)
at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:176)
at $Proxy31.start(Unknown Source)
at org.jboss.web.AbstractWebContainer.start(AbstractWebContainer.java:31
3)
at org.jboss.deployment.MainDeployer.start(MainDeployer.java:836)
at org.jboss.deployment.MainDeployer.start(MainDeployer.java:828)
at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:645)
at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:608)
at sun.reflect.GeneratedMethodAccessor14.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:582)
at org.jboss.mx.server.ReflectedDispatcher.dispatch(ReflectedDispatcher.
java:60)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:61)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:53)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.
java:185)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:473)
at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:176)
at $Proxy7.deploy(Unknown Source)
at org.jboss.deployment.scanner.URLDeploymentScanner.deploy(URLDeploymen
tScanner.java:304)
at org.jboss.deployment.scanner.URLDeploymentScanner.scan(URLDeploymentS
canner.java:460)
at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.
doScan(AbstractDeploymentScanner.java:201)
at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.
loop(AbstractDeploymentScanner.java:212)
at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.
run(AbstractDeploymentScanner.java:191)
16:14:23,031 ERROR [Engine] ----- Root Cause -----
java.lang.NullPointerException
at org.jboss.mx.loading.LoadMgr3.beginLoadTask(LoadMgr3.java:143)
at org.jboss.mx.loading.UnifiedClassLoader3.loadClassImpl(UnifiedClassLo
ader3.java:178)
at org.jboss.mx.loading.UnifiedClassLoader3.loadClass(UnifiedClassLoader
3.java:132)
at java.lang.ClassLoader.loadClass(ClassLoader.java:236)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:303)
at org.apache.struts.action.ActionServlet.destroyModules(ActionServlet.j
ava:719)
at org.apache.struts.action.ActionServlet.destroy(ActionServlet.java:430
)
at org.apache.catalina.core.StandardWrapper.unload(StandardWrapper.java:
1245)
at org.apache.catalina.core.StandardWrapper.stop(StandardWrapper.java:15
70)
at org.apache.catalina.core.ContainerBase.removeChild(ContainerBase.java
:952)
at org.apache.catalina.core.StandardContext.removeChild(StandardContext.
java:3126)
at org.apache.catalina.startup.ContextConfig.stop(ContextConfig.java:676
)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfi
g.java:218)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(Lifecycl
eSupport.java:119)
at org.apache.catalina.core.StandardContext.stop(StandardContext.java:44
87)
at org.apache.catalina.core.ContainerBase.destroy(ContainerBase.java:121
3)
at org.apache.catalina.core.StandardContext.destroy(StandardContext.java
:4573)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:582)
at org.apache.commons.modeler.BaseModelMBean.invoke(BaseModelMBean.java:
503)
at org.jboss.mx.server.RawDynamicInvoker.invoke(RawDynamicInvoker.java:1
09)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:473)
at org.jboss.web.tomcat.tc5.TomcatDeployer.performDeployInternal(TomcatD
eployer.java:142)
at org.jboss.web.tomcat.tc5.TomcatDeployer.performDeploy(TomcatDeployer.
java:70)
at org.jboss.web.AbstractWebDeployer.start(AbstractWebDeployer.java:306)

at org.jboss.web.WebModule.startModule(WebModule.java:62)
at org.jboss.web.WebModule.startService(WebModule.java:40)
at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanS
upport.java:271)
at org.jboss.system.ServiceMBeanSupport.jbossInternalLifecycle(ServiceMB
eanSupport.java:221)
at sun.reflect.GeneratedMethodAccessor73.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:582)
at org.jboss.mx.server.ReflectedDispatcher.dispatch(ReflectedDispatcher.
java:60)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:61)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:53)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.
java:185)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:473)
at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceControl
ler.java:837)
at $Proxy17.start(Unknown Source)
at org.jboss.system.ServiceController.start(ServiceController.java:367)
at sun.reflect.GeneratedMethodAccessor5.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:582)
at org.jboss.mx.server.ReflectedDispatcher.dispatch(ReflectedDispatcher.
java:60)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:61)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:53)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.
java:185)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:473)
at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:176)
at $Proxy31.start(Unknown Source)
at org.jboss.web.AbstractWebContainer.start(AbstractWebContainer.java:31
3)
at org.jboss.deployment.MainDeployer.start(MainDeployer.java:836)
at org.jboss.deployment.MainDeployer.start(MainDeployer.java:828)
at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:645)
at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:608)
at sun.reflect.GeneratedMethodAccessor14.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:582)
at org.jboss.mx.server.ReflectedDispatcher.dispatch(ReflectedDispatcher.
java:60)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:61)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:53)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.
java:185)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:473)
at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:176)
at $Proxy7.deploy(Unknown Source)
at org.jboss.deployment.scanner.URLDeploymentScanner.deploy(URLDeploymen
tScanner.java:304)
at org.jboss.deployment.scanner.URLDeploymentScanner.scan(URLDeploymentS
canner.java:460)
at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.
doScan(AbstractDeploymentScanner.java:201)
at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.
loop(AbstractDeploymentScanner.java:212)
at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.
run(AbstractDeploymentScanner.java:191)

[bjornbak]

Yes, I experience the same error periodically. I can't find a way to reproduce the error on command...

I use Struts too, but I hadn't linked the error to Struts...

[randahl]

Sure it is related to Struts. Look:

"Servlet action threw unload()"

And in my system the servlet name "action" refers to the Struts action servlet. This is confirmed by the fact that if I disable struts, the problem goes away. As soon as struts is enabled, the error occurs - even if I disable all my own struts stuff and run a clean, fresh struts install the error occurs...

Anyone got any ideas?

Randahl

[lviz]

hi randahl

yes, some ideas ;)

be ABSOLUT sure that all your apps use the SAME struts version

you can try to use the tomcat specific class loader..
(that may help !?)
edit: /deploy/jbossweb-tomcat50.sar/META-INF/jboss-service.xml

<attribute name="UseJBossWebLoader">false</attribute>

I/we had several problems with several struts/jboss versions

i use jboss3.2.5 and struts 1.2.1 and struts-layout-latest and Tomcat Webloader.
everything works fine now.

cheers
L

[randahl]

Unfortunately setting this to false yields a huge amount of FileNotFoundExceptions related to different kinds of ".bsh" files like the following

java.io.FileNotFoundException: C:\jboss-3.2.5\server\shared\tmp\de
ploy\tmp17849web-console.war\WEB-INF\classes\SystemFolder.bsh

I tried wiping the deploy folder but this leads to even more errors like

java.io.FileNotFoundException: C:\jboss-3.2.5\server\shared\work\j
boss.web\localhost\_\loader\org\apache\struts\resources\struts-config_1_1.dtd

For now I will go back to using the UseJBossWebLoader=true setting. - Why did you think this was the solution in the first place, and do you have any idea why it leads to the exceptions above?

[randahl]

By the way you did mean struts 1.1, right? Not 1.2.1?

I am using struts 1.1 and its jar is in the web-inf/lib folder of my war.

Randahl

[lviz]

hi randahl

we use "struts 1.2.1"

UseJBossWebLoader: A flag indicating if the class loader used by Tomcat as the web application class loader is a JBoss unified class loader. The default is true, and this means that the classes available in the war inside of the WEB-INF/classes and WEB-INF/jars are incorporated into the default shared class loader repository described in chapter 2. This may not be what you want as its contrary to the default servlet 3.2 class loading model and can result in sharing of classes/resources between web applications. You can disable this by setting this attribute to false.


different struts versions in wars,ears... what a mess ;)
... we had problems with sharing struts things between apps, so we used
UseJBossWebLoader "false".



we use the "all" configuration ..
you have to restart jboss if you change the UseJBossWebLoader..
clean the tmp and work directory after shutdown..

cheers
L