Hi,
We're currently getting quite a few stack dumps in our production
application (like the one at the bottom of this e-mail) where there is
no stack information indicating where a Null Pointer Exception occurred.
Instead, all we see is where the RequestProcessor (Struts 1.1) threw a
new exception. Originally, I assumed the NPE occurred somewhere in our
presentation or business tier classes. But looking at the Struts code,
it looks like Struts may have been unable to execute the specified
action (code snippets from RequestProcessor) object:
protected ActionForward processActionPerform(...) throws IOException,
ServletException {
try {
return (action.execute(mapping, form, request, response));
} catch (Exception e) {
return (processException(request, response, e, form, mapping));
}
}
protected ActionForward processException(...) throws IOException,
ServletException {
// Is there a defined handler for this exception?
ExceptionConfig config = mapping.findException(exception.getClass());
if (config == null) {
log.warn(getInternal().getMessage("unhandledException",
exception.getClass()));
if (exception instanceof IOException) {
throw (IOException) exception;
} else if (exception instanceof ServletException) {
throw (ServletException) exception;
} else {
throw new ServletException(exception); <-- New exception being
thrown here???
}
}
// Use the configured exception handling
<snip - we're not using configured exception handling>
}
So then I started checking things that would cause Struts problems, such
as checking
a) the name and package of my classes (comparing to the one declared in
my struts-config file)
b) that the class extends o.a.struts.action.Action
c) the signature of the 'execute' method
But everything looked good. In addition, when I execute the same URL in
our test environments. I don't see this problem. It appears to be
sporadic. Does anyone have any ideas on how I can further troubleshoot
these NPEs or obtain the complete stack trace. Without this
information, it's virtually impossible to figure out what the root cause
is.
Thanks,
JOHN
2004-05-03 10:01:16,413 ExecuteThread: '39' for queue: 'default' WARN
org.apache.struts.action.RequestProcessor - Unhandled Exception thrown:
class java.lang.NullPointerException
2004-05-03 10:01:16,413 ExecuteThread: '39' for queue: 'default' ERROR
com.erac.fleetsystems.strutsx.FleetSystemsServlet - Error processing
HTTP request - javax.servlet.ServletException
javax.servlet.ServletException
at
org.apache.struts.action.RequestProcessor.processException(RequestProces
sor.java(Compiled Code))
at
org.apache.struts.action.RequestProcessor.processActionPerform(RequestPr
ocessor.java(Inlined Compiled Code))
at
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java(
Compiled Code))
at
org.apache.struts.action.ActionServlet.process(ActionServlet.java(Compil
ed Code))
at
com.erac.fleetsystems.strutsx.FleetSystemsServlet.process(FleetSystemsSe
rvlet.java(Compiled Code))
at
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java(Compile
d Code))
at javax.servlet.http.HttpServlet.service(HttpServlet.java(Compiled
Code))
at javax.servlet.http.HttpServlet.service(HttpServlet.java(Compiled
Code))
at
weblogic.servlet.internal.ServletStubImpl$ServletInvocationAction.run(Se
rvletStubImpl.java(Compiled Code))
at
weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.
java(Compiled Code))
at
weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java(Compiled
Code))
at
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java(
Compiled Code))
at
com.erac.edge.presentation.util.EdgeUowFilter.doFirstTimeFilter(EdgeUowF
ilter.java(Compiled Code))
at
com.erac.fleetsystems.strutsx.FirstTimeOnlyFilter.doFilter(FirstTimeOnly
Filter.java(Compiled Code))
at
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java(
Inlined Compiled Code))
at
com.erac.edge.presentation.util.LoggingFilter.doFirstTimeFilter(LoggingF
ilter.java(Compiled Code))
at
com.erac.fleetsystems.strutsx.FirstTimeOnlyFilter.doFilter(FirstTimeOnly
Filter.java(Compiled Code))
at
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java(
Inlined Compiled Code))
at
weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.r
un(WebAppServletContext.java(Compiled Code))
at
weblogic.security.service.SecurityServiceManager.runAs(SecurityServiceMa
nager.java(Compiled Code))
at
weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServl
etContext.java(Compiled Code))
at
weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.
java(Compiled Code))
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java(Compiled
Code))
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:210)
