AssertionError in WildcardTypeImpl.getUpperBoundASTs

Peter Levart peter.levart at
Tue Oct 17 10:13:28 UTC 2017

Hi Dawid,

The [2] mentions a thread which resulted in a patch by Martin Bucholtz 
for JDK 9:

...but it seems this has not been backported to 8u (yet). The question 
is, will there be any more 8u releases? Would you like this to be 
backported to 8u?

Regards, Peter

On 10/13/2017 09:53 AM, Dawid Weiss wrote:
> Hi all,
> We are observing very infrequent assertion errors originating in
> getUpperBoundASTs, mostly during concurrent builds on our build
> machine, when it's under a heavy load. This has been happening from
> time to time with various Java versions; most recently with 1.8.0_131.
> I don't see anything in Jira about it, but even a quick Google search
> yields some hits [1].
> The stack trace starts with (I include the jackson stack frame which calls it):
> java.lang.AssertionError: null
> at sun.reflect.generics.reflectiveObjects.WildcardTypeImpl.getUpperBoundASTs(
> ~[?:1.8.0_131]
> at sun.reflect.generics.reflectiveObjects.WildcardTypeImpl.getUpperBounds(
> ~[?:1.8.0_131]
> at com.fasterxml.jackson.databind.type.TypeFactory._fromWildcard(
> ~[jackson-databind-2.8.2.jar:2.8.2]
> The problem cannot be easily reproduced, but I see a comment mentioned
> on the core-libs-dev a while ago [2] by Joel Borggrén-Franck, so
> perhaps his question is a valid one and worth investigating:
>> Btw, has anyone seen the assert for upper/lower bounds == null fail in the wild?
> Dawid
> [1]
> (note the "[JENKINS] Lucene-olr-master-Linux" hit).
> [2]

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