Proxy classes and reflection (IllegalAccessException)

[Dawid Weiss]

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
>> >>>
>> >>>
>>
>>