Proxy classes and reflection (IllegalAccessException)

[Emmanuel Bernard]

Hey Dawid,

Could you create an issue on the RestEasy tracker. That's useful feedback and we should fix it at the root sooner than later. 

> On 7 avr. 2016, at 19:48, Dawid Weiss <dawid.weiss at gmail.com> wrote:
> 
> Thanks to everyone for contributing. Here's my quick summary:
> 
> 1) "I assume it should be using newProxyInstance rather that trying to
> instantiate the proxy class directly."
> 
> Let's assume I have no control over the code of RestEasy. Yes, I could
> patch it locally, but I imagine most people (including me) would want to
> stick to public versions and provide some other kinds of "external" workarounds
> (like magic switches to java) rather than fork X libraries and keep
> their custom versions up-to-date until they are fixed.
> 
> 2) so the solution is easier to add a read edge in the code of
> RestEasy as Stephane said [...]
> 
> Hmm... how do I add this "read edge"? And to what? Can -XaddExports or
> -XaddReads
> reference module jdk.proxy2? I think I tried to append addExports from
> jdk.proxy2 to unnamed modules but Java complained there is no such
> module (jdk.proxy2) to add exports to.
> 
> Apologies if my questions are lame, sadly I didn't have time to try
> jigsaw before (or rather: everything worked pretty much fine in Lucene
> and other self-contained software I tried it on). This code I'm
> working on now is much more complex.
> 
> Dawid
> 
>> On Thu, Apr 7, 2016 at 3:29 PM, Remi Forax <forax at univ-mlv.fr> wrote:
>> The problem is that RestEasy is using getProxyClass() which is deprecated in 9.
>> 
>> RestEasy want to do a call to Constructor.newInstance on a constructor of the proxy class,
>> and as Stephane said, RestEasy (which is in the unamed module in your case) do not have access to the proxy class which is in a dynamic module
>> 
>> quote from the javadoc of j.l.r.Proxy
>> "
>> Dynamic Modules
>> 
>> A dynamic module is a named module generated at runtime. A proxy class defined in a dynamic module is encapsulated and not accessible to any module. Calling Constructor.newInstance(Object...) on a proxy class in a dynamic module will throw IllegalAccessException; Proxy.newProxyInstance method should be used instead.
>> "
>> 
>> so the solution is easier to add a read edge in the code of RestEasy as Stephane said or to change the code of RestEasy to use newProxyInstance() instead.
>> 
>> regards,
>> Rémi
>> 
>> ----- Mail original -----
>>> De: "Stephane Epardaud" <stef at epardaud.fr>
>>> À: jigsaw-dev at openjdk.java.net
>>> Envoyé: Jeudi 7 Avril 2016 15:02:28
>>> Objet: Re: Proxy classes and reflection (IllegalAccessException)
>>> 
>>> No, you have to add a read to the module of the class you're proxying,
>>> not com.sun.proxy. That'd be your application's module.
>>> 
>>>> On 07/04/16 14:25, Neil Bartlett wrote:
>>>> Stephane, I don’t think that would help since the package is not exported:
>>>> "module jdk.proxy2 does not export com.sun.proxy.jdk.proxy2”.
>>>> 
>>>> Regards,
>>>> Neil
>>>> 
>>>>> On 7 Apr 2016, at 13:13, Stephane Epardaud <stef at epardaud.fr> wrote:
>>>>> 
>>>>> IIRC RestEasy needs to add a module read to that Class's module it wants
>>>>> to create a Proxy of.
>>>>> 
>>>>>> On 07/04/16 14:05, Alan Bateman wrote:
>>>>>>> On 07/04/2016 12:39, Dawid Weiss wrote:
>>>>>>> I don't want to hijack the other thread, so here's a new one I'm stuck
>>>>>>> with. I get this exception (simplified stack trace a bit):
>>>>>>> 
>>>>>>> Caused by: java.lang.IllegalAccessException: class
>>>>>>> org.jboss.resteasy.core.ContextParameterInjector cannot access class
>>>>>>> com.sun.proxy.jdk.proxy2.$Proxy65 (in module jdk.proxy2) because
>>>>>>> module jdk.proxy2 does not export com.sun.proxy.jdk.proxy2 to unnamed
>>>>>>> module @79ca92b9
>>>>>>> at
>>>>>>> sun.reflect.Reflection.throwIllegalAccessException(java.base at 9-ea/Reflection.java:411)
>>>>>>> at
>>>>>>> sun.reflect.Reflection.throwIllegalAccessException(java.base at 9-ea/Reflection.java:402)
>>>>>>> at
>>>>>>> sun.reflect.Reflection.ensureMemberAccess(java.base at 9-ea/Reflection.java:99)
>>>>>>> at
>>>>>>> java.lang.reflect.AccessibleObject.slowCheckMemberAccess(java.base at 9-ea/AccessibleObject.java:355)
>>>>>>> at
>>>>>>> java.lang.reflect.AccessibleObject.checkAccess(java.base at 9-ea/AccessibleObject.java:347)
>>>>>>> at
>>>>>>> java.lang.reflect.Constructor.newInstance(java.base at 9-ea/Constructor.java:444)
>>>>>>> at
>>>>>>> org.jboss.resteasy.core.ContextParameterInjector.createProxy(ContextParameterInjector.java:94)
>>>>>>> ... 53 more
>>>>>>> 
>>>>>>> I think RestEasy attempts to do create a new instance of a proxy class
>>>>>>> here (the complete process here eludes my understanding for now). Any
>>>>>>> clues how this can be solved?
>>>>>> I assume it should be using newProxyInstance rather that trying to
>>>>>> instantiate the proxy class directly. The reason it can't instantiate it
>>>>>> directly is because it has been generated into a "dynamic module"
>>>>>> (jdk.proxy2 in this case). I assume you'll find that the proxy was
>>>>>> created with an interface that is not in an exported package.
>>>>>> 
>>>>>> The "Package and Module Membership of Proxy Class" and "Dynamic Modules"
>>>>>> sections of the Proxy javadoc [1] has all the details.
>>>>>> 
>>>>>> -Alan.
>>>>>> 
>>>>>> [1]
>>>>>> http://download.java.net/java/jdk9/docs/api/java/lang/reflect/Proxy.html
>>> 
>>>