feedback on --permit-illegal-access

Alan Bateman Alan.Bateman at
Fri Apr 7 07:11:11 UTC 2017

On 07/04/2017 00:09, Jochen Theodorou wrote:

> Hi,
> so today I found finally _JAVA_OPTIONS to get our gradle build running 
> and of course I used --permit-illegal-access and I thought I give some 
> feedback here.
> Running a clean test on our build will result in 44531 warning 
> messages. Of which 6394 are unique. of course some of those warnings 
> are actually from gradle and some are from xstream, but that makes 
> maybe 21 less.
> Why do we have such a huge amount of warnings? That is because of the 
> way we are building our meta classes, which we still have to change 
> and use JDK9 special code (something we tried to avoid)
The implementation makes a best effort to avoid emitting duplicate 
warnings. Are these 44531 warnings coming from one run of the VM or is 
this the total from many `java` commands run in the build? Another 
possibility is code generation. The filtering of duplicates is based on 
the perpetrator's call stack and the victim. If Groovy is generating a 
lot of classes and the code is say using a shared utility class to hack 
in then these usages would not be unique.

Running with -Dsun.reflect.debugModuleAccessChecks=access will give you 
a full stack trace at each warning and should help debug this.


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