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Posted to users@tomcat.apache.org by Adam Jenkins <Ad...@nti.com.au> on 2008/08/19 08:05:00 UTC
NullPointerException 5.5.17 Request.setAttribute(Request.java:1376)
Hi All,
I'be been tearing my hair out for a couple of weeks over this one and would appreciate any assistance anyone could give. It's a bit of a unique scenario, so it'll take me a little while to explain:
We have a legacy struts app, forwarding to a jsf app (details of how below) running on tomcat 5.5.17. 99.9% of the time everythign works great, but every now and then (which in users speak translates to 'I keep on getting', hence we can't ignore it) a NullPointerException gets thrown from org.apache.catalina.connector.Request.setAttribute.
The flow is:
Third party application ---<<http redirect>>---> JSFBridgeFilter (will explain later) -----> Struts application ----> JSFBridge--->JSF Application--->Response back to third party app.
The struts application contains proprietary logic to interface with the third party app, so we can't get rid of it. Business wants all development internally to be done in JSF, so we can't get rid of that.
The JSFBridgeFilter instantiates the JSF Context for later use, and wraps the request that is used to instantiate it in a request wrapper that translates ".do" context paths to ".jsf" context paths (otherwise all the forms submit back to ".do" after coming from the struts framework. It looks like this:
public void doFilter(ServletRequest strutsRequest, ServletResponse response, FilterChain chain) throws IOException, ServletException {
HttpServletRequest jsfRequest = new StrutsToJsfRequestWrapper((HttpServletRequest)strutsRequest);
JSFBridge.getFacesContext(viewId, (HttpServletRequest)jsfRequest, (HttpServletResponse)response);
chain.doFilter(strutsRequest, response);
}
...and the StrutsToJsfRequestWrapper contains only one override method (it extends HttpServletRequestWrapper):
@Override
public String getServletPath() {
String oldPath = super.getServletPath();
String newPath = null;
int index = oldPath.lastIndexOf(".do");
if (index >= 0) {
newPath = oldPath.substring(0, index + 1) + ".jsf";
} else {
newPath = oldPath;
}
return newPath;
}
Now, you'll notice in the filter that the request wrapper is used to instantiate the faces context, and the original request passed onto the struts application. The 'getFacesContext' method implements some code from the apache myfaces wiki that shows a way to call into the JSF framework from non jsf artifacts:
It looks like this:
public class JSFBridge {
private abstract static class InnerFacesContext extends FacesContext {
protected static void setFacesContextAsCurrentInstance(final FacesContext facesContext) {
FacesContext.setCurrentInstance(facesContext);
}
}
public static FacesContext getFacesContext(final String viewId, final ServletRequest request, final ServletResponse response) {
FacesContext facesContext = FacesContext.getCurrentInstance();
if (facesContext != null) {
return facesContext;
}
return getNewFacesContext(viewId, request, response);
}
public static FacesContext getNewFacesContext(final String viewId, final ServletRequest request, final ServletResponse response) {
FacesContext facesContext;
FacesContextFactory contextFactory = (FacesContextFactory) FactoryFinder.getFactory(FactoryFinder.FACES_CONTEXT_FACTORY);
LifecycleFactory lifecycleFactory = (LifecycleFactory) FactoryFinder.getFactory(FactoryFinder.LIFECYCLE_FACTORY);
Lifecycle lifecycle = lifecycleFactory.getLifecycle(LifecycleFactory.DEFAULT_LIFECYCLE);
facesContext = contextFactory.getFacesContext(((HttpServletRequest)request).getSession().getServletContext(),request, response, lifecycle);
InnerFacesContext.setFacesContextAsCurrentInstance(facesContext);
UIViewRoot view = facesContext.getApplication().getViewHandler().createView(facesContext, viewId);
facesContext.setViewRoot(view);
return facesContext;
}
}
And the final piece of the puzzle is a struts action that actually loads the context and forwards to the appropriate JSF method...which looks like this:
public class ForwardToJSFAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {
JSFMapping viewMapping = (JSFMapping) mapping;
FacesContext ctx = JSFBridge.getFacesContext(viewMapping.getViewId(), request, response);
MethodBinding mb = lookupMethodBinding(viewMapping, ctx);
navigateToMethodBinding(viewMapping, ctx, mb);
return null;
}
private MethodBinding lookupMethodBinding(JSFMapping viewMapping, FacesContext ctx) {
return ctx.getApplication().createMethodBinding("#{" + viewMapping.getJsfAction() + "}", new Class[] {});
}
private void navigateToMethodBinding(JSFMapping viewMapping, FacesContext ctx, MethodBinding mb) {
Object obj = mb.invoke(ctx, new Object[] {});
NavigationHandler navHandler = ctx.getApplication().getNavigationHandler();
navHandler.handleNavigation(ctx, "#{" + viewMapping.getJsfAction() + "}", (String) obj);
}
}
Now, as odd as all this looks, it actually works quite well in 99.9% of the cases. We get a request in struts, which forwards quite nicely onto a JSF method and completes the business process in JSF. Every now and then though, we get the following error when we try to invoke the method binding:
Caused by: java.lang.NullPointerException
at org.apache.catalina.connector.Request.setAttribute(Request.java:1376)
at org.apache.catalina.connector.RequestFacade.setAttribute(RequestFacade.java:500)
at javax.servlet.ServletRequestWrapper.setAttribute(ServletRequestWrapper.java:283)
at org.apache.myfaces.context.servlet.RequestMap.setAttribute(RequestMap.java:46)
at org.apache.myfaces.context.servlet.AbstractAttributeMap.put(AbstractAttributeMap.java:104)
at org.apache.myfaces.el.VariableResolverImpl.resolveVariable(VariableResolverImpl.java:301)
at org.apache.myfaces.config.LastVariableResolverInChain.resolveVariable(LastVariableResolverInChain.java:42)
at org.apache.myfaces.el.ValueBindingImpl$ELVariableResolver.resolveVariable(ValueBindingImpl.java:574)
at org.apache.commons.el.NamedValue.evaluate(NamedValue.java:124)
at org.apache.myfaces.el.ValueBindingImpl.resolveToBaseAndProperty(ValueBindingImpl.java:455)
at org.apache.myfaces.el.MethodBindingImpl.resolveToBaseAndProperty(MethodBindingImpl.java:180)
at org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:114)
Diving into Request.java(Line 1376), shows that it's happening on this line:
Object listeners[] = context.getApplicationEventListeners();
So I'm guessing that 'context' is null for some reason. Since it is so rare, it's almost impossible to reproduce in a manner consistent enough to actually diagnose and debug it.
Can anyone see, from the above, anything that could shed some light on this?
Cheers
Adam
Number 1 in Truck Insurance
______________________________________________________________________
CAUTION - This message is intended for the addressee named above.
It may contain privileged or confidential information. If you are
not the intended recipient of this message you must not use,
copy, distribute or disclose it to anyone other than the addressee.
If you have received this email in error please return the message to the sender by replying to it and then delete the message from your computer.
Internet e-mails are not necessarily secure.
National Transport Insurance does not accept responsibility for changes made to this message after it was sent.
______________________________________________________________________
FW: NullPointerException 5.5.17 Request.setAttribute(Request.java:1376)
Posted by Adam Jenkins <Ad...@nti.com.au>.
Hi, I've sent the following to the tomcat mailing lists for advice, but since it also involves myfaces I thought I'd send it here too. I hope someone, somewhere has some idea as to what's going on.
Cheers
Adam
________________________________
From: Adam Jenkins [mailto:AdamJenkins@nti.com.au]
Sent: Tue 19/08/2008 4:05 PM
To: users@tomcat.apache.org
Subject: NullPointerException 5.5.17 Request.setAttribute(Request.java:1376)
Hi All,
I'be been tearing my hair out for a couple of weeks over this one and would appreciate any assistance anyone could give. It's a bit of a unique scenario, so it'll take me a little while to explain:
We have a legacy struts app, forwarding to a jsf app (details of how below) running on tomcat 5.5.17. 99.9% of the time everythign works great, but every now and then (which in users speak translates to 'I keep on getting', hence we can't ignore it) a NullPointerException gets thrown from org.apache.catalina.connector.Request.setAttribute.
The flow is:
Third party application ---<<http redirect>>---> JSFBridgeFilter (will explain later) -----> Struts application ----> JSFBridge--->JSF Application--->Response back to third party app.
The struts application contains proprietary logic to interface with the third party app, so we can't get rid of it. Business wants all development internally to be done in JSF, so we can't get rid of that.
The JSFBridgeFilter instantiates the JSF Context for later use, and wraps the request that is used to instantiate it in a request wrapper that translates ".do" context paths to ".jsf" context paths (otherwise all the forms submit back to ".do" after coming from the struts framework. It looks like this:
public void doFilter(ServletRequest strutsRequest, ServletResponse response, FilterChain chain) throws IOException, ServletException {
HttpServletRequest jsfRequest = new StrutsToJsfRequestWrapper((HttpServletRequest)strutsRequest);
JSFBridge.getFacesContext(viewId, (HttpServletRequest)jsfRequest, (HttpServletResponse)response);
chain.doFilter(strutsRequest, response);
}
...and the StrutsToJsfRequestWrapper contains only one override method (it extends HttpServletRequestWrapper):
@Override
public String getServletPath() {
String oldPath = super.getServletPath();
String newPath = null;
int index = oldPath.lastIndexOf(".do");
if (index >= 0) {
newPath = oldPath.substring(0, index + 1) + ".jsf";
} else {
newPath = oldPath;
}
return newPath;
}
Now, you'll notice in the filter that the request wrapper is used to instantiate the faces context, and the original request passed onto the struts application. The 'getFacesContext' method implements some code from the apache myfaces wiki that shows a way to call into the JSF framework from non jsf artifacts:
It looks like this:
public class JSFBridge {
private abstract static class InnerFacesContext extends FacesContext {
protected static void setFacesContextAsCurrentInstance(final FacesContext facesContext) {
FacesContext.setCurrentInstance(facesContext);
}
}
public static FacesContext getFacesContext(final String viewId, final ServletRequest request, final ServletResponse response) {
FacesContext facesContext = FacesContext.getCurrentInstance();
if (facesContext != null) {
return facesContext;
}
return getNewFacesContext(viewId, request, response);
}
public static FacesContext getNewFacesContext(final String viewId, final ServletRequest request, final ServletResponse response) {
FacesContext facesContext;
FacesContextFactory contextFactory = (FacesContextFactory) FactoryFinder.getFactory(FactoryFinder.FACES_CONTEXT_FACTORY);
LifecycleFactory lifecycleFactory = (LifecycleFactory) FactoryFinder.getFactory(FactoryFinder.LIFECYCLE_FACTORY);
Lifecycle lifecycle = lifecycleFactory.getLifecycle(LifecycleFactory.DEFAULT_LIFECYCLE);
facesContext = contextFactory.getFacesContext(((HttpServletRequest)request).getSession().getServletContext(),request, response, lifecycle);
InnerFacesContext.setFacesContextAsCurrentInstance(facesContext);
UIViewRoot view = facesContext.getApplication().getViewHandler().createView(facesContext, viewId);
facesContext.setViewRoot(view);
return facesContext;
}
}
And the final piece of the puzzle is a struts action that actually loads the context and forwards to the appropriate JSF method...which looks like this:
public class ForwardToJSFAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {
JSFMapping viewMapping = (JSFMapping) mapping;
FacesContext ctx = JSFBridge.getFacesContext(viewMapping.getViewId(), request, response);
MethodBinding mb = lookupMethodBinding(viewMapping, ctx);
navigateToMethodBinding(viewMapping, ctx, mb);
return null;
}
private MethodBinding lookupMethodBinding(JSFMapping viewMapping, FacesContext ctx) {
return ctx.getApplication().createMethodBinding("#{" + viewMapping.getJsfAction() + "}", new Class[] {});
}
private void navigateToMethodBinding(JSFMapping viewMapping, FacesContext ctx, MethodBinding mb) {
Object obj = mb.invoke(ctx, new Object[] {});
NavigationHandler navHandler = ctx.getApplication().getNavigationHandler();
navHandler.handleNavigation(ctx, "#{" + viewMapping.getJsfAction() + "}", (String) obj);
}
}
Now, as odd as all this looks, it actually works quite well in 99.9% of the cases. We get a request in struts, which forwards quite nicely onto a JSF method and completes the business process in JSF. Every now and then though, we get the following error when we try to invoke the method binding:
Caused by: java.lang.NullPointerException
at org.apache.catalina.connector.Request.setAttribute(Request.java:1376)
at org.apache.catalina.connector.RequestFacade.setAttribute(RequestFacade.java:500)
at javax.servlet.ServletRequestWrapper.setAttribute(ServletRequestWrapper.java:283)
at org.apache.myfaces.context.servlet.RequestMap.setAttribute(RequestMap.java:46)
at org.apache.myfaces.context.servlet.AbstractAttributeMap.put(AbstractAttributeMap.java:104)
at org.apache.myfaces.el.VariableResolverImpl.resolveVariable(VariableResolverImpl.java:301)
at org.apache.myfaces.config.LastVariableResolverInChain.resolveVariable(LastVariableResolverInChain.java:42)
at org.apache.myfaces.el.ValueBindingImpl$ELVariableResolver.resolveVariable(ValueBindingImpl.java:574)
at org.apache.commons.el.NamedValue.evaluate(NamedValue.java:124)
at org.apache.myfaces.el.ValueBindingImpl.resolveToBaseAndProperty(ValueBindingImpl.java:455)
at org.apache.myfaces.el.MethodBindingImpl.resolveToBaseAndProperty(MethodBindingImpl.java:180)
at org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:114)
Diving into Request.java(Line 1376), shows that it's happening on this line:
Object listeners[] = context.getApplicationEventListeners();
So I'm guessing that 'context' is null for some reason. Since it is so rare, it's almost impossible to reproduce in a manner consistent enough to actually diagnose and debug it.
Can anyone see, from the above, anything that could shed some light on this?
Cheers
Adam
Number 1 in Truck Insurance
______________________________________________________________________
CAUTION - This message is intended for the addressee named above.
It may contain privileged or confidential information. If you are
not the intended recipient of this message you must not use,
copy, distribute or disclose it to anyone other than the addressee.
If you have received this email in error please return the message to the sender by replying to it and then delete the message from your computer.
Internet e-mails are not necessarily secure.
National Transport Insurance does not accept responsibility for changes made to this message after it was sent.
______________________________________________________________________
Number 1 in Truck Insurance
______________________________________________________________________
CAUTION - This message is intended for the addressee named above.
It may contain privileged or confidential information. If you are
not the intended recipient of this message you must not use,
copy, distribute or disclose it to anyone other than the addressee.
If you have received this email in error please return the message to the sender by replying to it and then delete the message from your computer.
Internet e-mails are not necessarily secure.
National Transport Insurance does not accept responsibility for changes made to this message after it was sent.
______________________________________________________________________
Re: NullPointerException 5.5.17 Request.setAttribute(Request.java:1376)
Posted by Mark Thomas <ma...@apache.org>.
Adam Jenkins wrote:
> Hi All,
> I'be been tearing my hair out for a couple of weeks over this one and would appreciate any assistance anyone could give. It's a bit of a unique scenario, so it'll take me a little while to explain:
> We have a legacy struts app, forwarding to a jsf app (details of how below) running on tomcat 5.5.17. 99.9% of the time everythign works great, but every now and then (which in users speak translates to 'I keep on getting', hence we can't ignore it) a NullPointerException gets thrown from org.apache.catalina.connector.Request.setAttribute.
Looks like a threading issue. There is a problem with RequestDispatcher
that *might* be affecting you in 5.5.17 that is fixed in 5.5.21 - it only
occurs if you reuse the same request dispatcher object for multiple requests.
It that isn't it, look for cases in your code where you store the request
object for later re-use.
Mark
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NullPointerException 5.5.17 Request.setAttribute(Request.java:1376)
Posted by Adam Jenkins <Ad...@nti.com.au>.
I sent the following to the tomcat mailing list. Since it also involves struts I thought I'd also send it on here and see if anyone has any ideas
Cheers
Adam
________________________________
From: Adam Jenkins [mailto:AdamJenkins@nti.com.au]
Sent: Tue 19/08/2008 4:05 PM
To: users@tomcat.apache.org
Subject: NullPointerException 5.5.17 Request.setAttribute(Request.java:1376)
Hi All,
I'be been tearing my hair out for a couple of weeks over this one and would appreciate any assistance anyone could give. It's a bit of a unique scenario, so it'll take me a little while to explain:
We have a legacy struts app, forwarding to a jsf app (details of how below) running on tomcat 5.5.17. 99.9% of the time everythign works great, but every now and then (which in users speak translates to 'I keep on getting', hence we can't ignore it) a NullPointerException gets thrown from org.apache.catalina.connector.Request.setAttribute.
The flow is:
Third party application ---<<http redirect>>---> JSFBridgeFilter (will explain later) -----> Struts application ----> JSFBridge--->JSF Application--->Response back to third party app.
The struts application contains proprietary logic to interface with the third party app, so we can't get rid of it. Business wants all development internally to be done in JSF, so we can't get rid of that.
The JSFBridgeFilter instantiates the JSF Context for later use, and wraps the request that is used to instantiate it in a request wrapper that translates ".do" context paths to ".jsf" context paths (otherwise all the forms submit back to ".do" after coming from the struts framework. It looks like this:
public void doFilter(ServletRequest strutsRequest, ServletResponse response, FilterChain chain) throws IOException, ServletException {
HttpServletRequest jsfRequest = new StrutsToJsfRequestWrapper((HttpServletRequest)strutsRequest);
JSFBridge.getFacesContext(viewId, (HttpServletRequest)jsfRequest, (HttpServletResponse)response);
chain.doFilter(strutsRequest, response);
}
...and the StrutsToJsfRequestWrapper contains only one override method (it extends HttpServletRequestWrapper):
@Override
public String getServletPath() {
String oldPath = super.getServletPath();
String newPath = null;
int index = oldPath.lastIndexOf(".do");
if (index >= 0) {
newPath = oldPath.substring(0, index + 1) + ".jsf";
} else {
newPath = oldPath;
}
return newPath;
}
Now, you'll notice in the filter that the request wrapper is used to instantiate the faces context, and the original request passed onto the struts application. The 'getFacesContext' method implements some code from the apache myfaces wiki that shows a way to call into the JSF framework from non jsf artifacts:
It looks like this:
public class JSFBridge {
private abstract static class InnerFacesContext extends FacesContext {
protected static void setFacesContextAsCurrentInstance(final FacesContext facesContext) {
FacesContext.setCurrentInstance(facesContext);
}
}
public static FacesContext getFacesContext(final String viewId, final ServletRequest request, final ServletResponse response) {
FacesContext facesContext = FacesContext.getCurrentInstance();
if (facesContext != null) {
return facesContext;
}
return getNewFacesContext(viewId, request, response);
}
public static FacesContext getNewFacesContext(final String viewId, final ServletRequest request, final ServletResponse response) {
FacesContext facesContext;
FacesContextFactory contextFactory = (FacesContextFactory) FactoryFinder.getFactory(FactoryFinder.FACES_CONTEXT_FACTORY);
LifecycleFactory lifecycleFactory = (LifecycleFactory) FactoryFinder.getFactory(FactoryFinder.LIFECYCLE_FACTORY);
Lifecycle lifecycle = lifecycleFactory.getLifecycle(LifecycleFactory.DEFAULT_LIFECYCLE);
facesContext = contextFactory.getFacesContext(((HttpServletRequest)request).getSession().getServletContext(),request, response, lifecycle);
InnerFacesContext.setFacesContextAsCurrentInstance(facesContext);
UIViewRoot view = facesContext.getApplication().getViewHandler().createView(facesContext, viewId);
facesContext.setViewRoot(view);
return facesContext;
}
}
And the final piece of the puzzle is a struts action that actually loads the context and forwards to the appropriate JSF method...which looks like this:
public class ForwardToJSFAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {
JSFMapping viewMapping = (JSFMapping) mapping;
FacesContext ctx = JSFBridge.getFacesContext(viewMapping.getViewId(), request, response);
MethodBinding mb = lookupMethodBinding(viewMapping, ctx);
navigateToMethodBinding(viewMapping, ctx, mb);
return null;
}
private MethodBinding lookupMethodBinding(JSFMapping viewMapping, FacesContext ctx) {
return ctx.getApplication().createMethodBinding("#{" + viewMapping.getJsfAction() + "}", new Class[] {});
}
private void navigateToMethodBinding(JSFMapping viewMapping, FacesContext ctx, MethodBinding mb) {
Object obj = mb.invoke(ctx, new Object[] {});
NavigationHandler navHandler = ctx.getApplication().getNavigationHandler();
navHandler.handleNavigation(ctx, "#{" + viewMapping.getJsfAction() + "}", (String) obj);
}
}
Now, as odd as all this looks, it actually works quite well in 99.9% of the cases. We get a request in struts, which forwards quite nicely onto a JSF method and completes the business process in JSF. Every now and then though, we get the following error when we try to invoke the method binding:
Caused by: java.lang.NullPointerException
at org.apache.catalina.connector.Request.setAttribute(Request.java:1376)
at org.apache.catalina.connector.RequestFacade.setAttribute(RequestFacade.java:500)
at javax.servlet.ServletRequestWrapper.setAttribute(ServletRequestWrapper.java:283)
at org.apache.myfaces.context.servlet.RequestMap.setAttribute(RequestMap.java:46)
at org.apache.myfaces.context.servlet.AbstractAttributeMap.put(AbstractAttributeMap.java:104)
at org.apache.myfaces.el.VariableResolverImpl.resolveVariable(VariableResolverImpl.java:301)
at org.apache.myfaces.config.LastVariableResolverInChain.resolveVariable(LastVariableResolverInChain.java:42)
at org.apache.myfaces.el.ValueBindingImpl$ELVariableResolver.resolveVariable(ValueBindingImpl.java:574)
at org.apache.commons.el.NamedValue.evaluate(NamedValue.java:124)
at org.apache.myfaces.el.ValueBindingImpl.resolveToBaseAndProperty(ValueBindingImpl.java:455)
at org.apache.myfaces.el.MethodBindingImpl.resolveToBaseAndProperty(MethodBindingImpl.java:180)
at org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:114)
Diving into Request.java(Line 1376), shows that it's happening on this line:
Object listeners[] = context.getApplicationEventListeners();
So I'm guessing that 'context' is null for some reason. Since it is so rare, it's almost impossible to reproduce in a manner consistent enough to actually diagnose and debug it.
Can anyone see, from the above, anything that could shed some light on this?
Cheers
Adam
Number 1 in Truck Insurance
______________________________________________________________________
CAUTION - This message is intended for the addressee named above.
It may contain privileged or confidential information. If you are
not the intended recipient of this message you must not use,
copy, distribute or disclose it to anyone other than the addressee.
If you have received this email in error please return the message to the sender by replying to it and then delete the message from your computer.
Internet e-mails are not necessarily secure.
National Transport Insurance does not accept responsibility for changes made to this message after it was sent.
______________________________________________________________________
Number 1 in Truck Insurance
______________________________________________________________________
CAUTION - This message is intended for the addressee named above.
It may contain privileged or confidential information. If you are
not the intended recipient of this message you must not use,
copy, distribute or disclose it to anyone other than the addressee.
If you have received this email in error please return the message to the sender by replying to it and then delete the message from your computer.
Internet e-mails are not necessarily secure.
National Transport Insurance does not accept responsibility for changes made to this message after it was sent.
______________________________________________________________________