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From Rainer Jung <rainer.j...@kippdata.de>
Subject Re: Large webapps in 7.0.29 and Annotation Scanning not respecting "metadata-complete"
Date Wed, 01 Aug 2012 12:49:19 GMT
On 01.08.2012 09:51, Mark Thomas wrote:
> On 01/08/2012 02:53, andreas palsson wrote:
>>
>> Good morning.
>>
>> After upgrading to 7.0.29, one of my larger webapps could no longer be deployed due
to "OutOfMemoryError".
>> As far as I know, this is related to the new feature of annotation scanning which
was enabled in v7.0.29 (see the stack trace below).
>>
>> Have anyone else experienced the same issue?
>
> There are multiple issues going on here. There have been reported
> previously and are understood. I'll try and explain the full story.
>
> The servlet spec requires (and the expert group (EG) confirmed) that
> Tomcat always scans for ServletContainerInitializers (SCIs), even if
> metadata-complete is true. Tomcat was changed to do this in 7.0.29.
>
> SCIs can have @HandlesTypes annotations. If one is present, Tomcat must
> scan every class and its hierarchy looking for matches to the
> HandlesTypes. Tomcat caches the results of this scan to speed up
> processing so it doesn't repeatedly scan the same classes. If A & B both
> inherit from C, when Tomcat scans A it also scans C and caches the
> result so it doesn't have to scan C again when checking B. Tomcat was
> caching more than it needed to making the cache excessively large. This
> is bug 53535 which has already been fixed and will be in 7.0.30 onwards.
>
> This then raises the question of how to turn of scanning for classes
> that match HandlesTypes. While the spec says that JARs excluded using an
> absolute-ordering are not scanned for matches to HandlesTypes it was
> unclear what is meant to happen when metadata-complete is true since
> ordering is ignored in that case.
>
> The EG has recently clarified this and stated that JARs excluded using
> an absolute-ordering are not scanned for matches to HandlesTypes
> regardless of the setting of metadata-complete. The discussion is not
> yet complete and we are waiting for it to conclude and before
> implementing the results of that discussion in 7.0.30.

Would "*.jar" in jarsToSkip (catalina.properties) be a workaround, or is 
that skip list also ignored for SCI / @HandlesTypes processing?

Regards,

Rainer


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