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https://issues.apache.org/jira/browse/WICKET-2979?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12898151#action_12898151
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Florian Wunderlich commented on WICKET-2979:
--------------------------------------------
An error while handling an error is certainly a possibility, but this is
already correctly implemented in RequestCycle.step() using the
handlingException flag. Handling fatal errors can never be more than a "best
effort" implementation, as you have already pointed out.
My point is that if there is a method that handles fatal errors, it should
handle ALL fatal errors, not just RuntimeException.
For example, StackOverflowError is usually caused by unchecked recursion,
certainly a programming mistake. In such a case, I want to log this error just
as I log a SQL error from the persistence provider, informing the maintenance
crew for the application, and then I want to show the user the usual error
page. There is no point in informing the system administrators because the
Servlet container reported an unhandled exception, or showing a generic error
page for the Servlet container instead of the applications error page.
AssertionError is pretty much the same - these also occur in production when
they are thrown explicitly, which is not uncommon (a grep over the JDK sources
for 6u21 shows 293 occurrences).
Thus, I propose that either RequestCycle.step() is not declared final, or that
Throwable is caught and handled pretty much like RuntimeException now, possibly
re-throwing it in an override-able method.
I do understand that you do not want to catch Throwable because you cannot
simply re-throw it, but this is also not uncommon (find -name *.java | xargs
grep 'catch *( *Throwable' | wc -l over the same JDK 6u21 sources finds 330
occurrences), and there can be just two cases of unchecked exceptions anyway:
Error or RuntimeException. Thus, the handling can be exactly like in
java.io.ObjectStreamClass.java:2110 for example - test for Error, then
RuntimeException - it must be one or the other.
> Handle Throwable instead of RuntimeException in RequestCycle.step()
> -------------------------------------------------------------------
>
> Key: WICKET-2979
> URL: https://issues.apache.org/jira/browse/WICKET-2979
> Project: Wicket
> Issue Type: Improvement
> Components: wicket
> Affects Versions: 1.4.9
> Reporter: Florian Wunderlich
> Assignee: Martin Grigorov
>
> RequestCycle.java:1346 catches only RuntimeException, thus AssertionError and
> similar are not caught. In case of an AJAX request, the container will
> respond with an error page which the user will never see.
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