ClassFileTransformer does not apply to anonymous classes

Rafael Winterhalter rafael.wth at
Thu Jan 21 22:14:29 UTC 2016

Hi Andrew,
if there is any update on the matter, I would of course love to hear about it.
Unfortunately, I never received an answer to my question, but maybe I
picked the wrong list.
Thank you for your support on this issue!
Regards, Rafael

2016-01-21 10:07 GMT+01:00 Andrew Dinn <adinn at>:
> Hi Rafael,
> On 01/12/15 12:45, Rafael Winterhalter wrote:
>> I can tell that this behavior has not only affected me as I had this
>> question comming up by multiple users of my open-source code generation
>> library.
>> What is your view on this?
>> Thank you for your feedback!
> I have an interest in this issue because I lead a Java agent-based
> project (Byteman). I have not (yet) come across a case where the
> behaviour you describe has affected the operation of my agent -- I
> suspect that is because it will never attempt to transform a class
> defined via Unsafe::defineAnonymousClass. However, I agree with you that
> this behaviour appears anomalous and the outcome you describe is
> counter-intuitive. I would be very interested to know if there was a
> good reason for excluding anonymous classes from transformation.
> regards,
> Andrew Dinn
> -----------
> Senior Principal Software Engineer
> Red Hat UK Ltd
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> Directors: Michael Cunningham (US), Michael O'Neill (Ireland), Paul
> Argiry (US)

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