creating proxies for interfaces with default methods

[Jochen Theodorou]

On 27.05.2016 08:58, forax at univ-mlv.fr wrote:
>
>
> ----- Mail original -----
>> De: "Jochen Theodorou" <blackdrag at gmx.org>
>> À: "Remi Forax" <forax at univ-mlv.fr>
>> Cc: "jigsaw-dev" <jigsaw-dev at openjdk.java.net>
>> Envoyé: Vendredi 27 Mai 2016 07:28:58
>> Objet: Re: creating proxies for interfaces with default methods
>>
>> On 26.05.2016 14:00, Remi Forax wrote:
>>> Not if you use Lookup.findSpecial() [1]
>>> Anyway, you can not use it because you can not get the Lookup object
>>> associated with the proxy class.
>>
>> which is why I did this:
>>
>>>        MethodHandles.Lookup.class.getDeclaredConstructor(Class.class,
>>>        int.class).
>>>        newInstance(interfaceClass, MethodHandles.Lookup.PRIVATE).
>>>        unreflectSpecial(method, interfaceClass).
>>>        bindTo(receiver);
>>
>> but that is not working anymore.
>
> ??, what's the exact error ?

>     java.lang.AssertionError: java.util.Comparator/2
>         at java.lang.invoke.MethodHandles$Lookup.toString(java.base at 9-ea/MethodHandles.java:792)
>         at java.lang.String.valueOf(java.base at 9-ea/String.java:2806)
>         at java.lang.StringBuilder.append(java.base at 9-ea/StringBuilder.java:135)
>         at java.lang.invoke.MemberName.makeAccessException(java.base at 9-ea/MemberName.java:867)
>         at java.lang.invoke.MethodHandles$Lookup.checkAccess(java.base at 9-ea/MethodHandles.java:1642)
>         at java.lang.invoke.MethodHandles$Lookup.checkMethod(java.base at 9-ea/MethodHandles.java:1582)
>         at java.lang.invoke.MethodHandles$Lookup.getDirectMethodCommon(java.base at 9-ea/MethodHandles.java:1731)
>         at java.lang.invoke.MethodHandles$Lookup.getDirectMethodNoSecurityManager(java.base at 9-ea/MethodHandles.java:1725)
>         at java.lang.invoke.MethodHandles$Lookup.unreflectSpecial(java.base at 9-ea/MethodHandles.java:1336)
>         at org.codehaus.groovy.vmplugin.v7.Java7.getInvokeSpecialHandle(Java7.java:96)
>         at org.codehaus.groovy.runtime.ConversionHandler.invoke(ConversionHandler.java:109)
>         at com.sun.proxy.$Proxy47.reversed(Unknown Source)
>         at java_util_Comparator$reversed$0.call(Unknown Source)
>         at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
>         at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
>         at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:117)
>         at org.codehaus.groovy.runtime.InterfaceConversionTest.testDefaultInterfaceMethodCallOnProxy(InterfaceConversionTest.groovy:52)

my code uses MethodHandles.Lookup.PRIVATE only, which the implementation 
no longer allows in this case. I had not yet time to investigate if 
another mode works.

>>> That's why i've written the Proxy2 library [2].
>>>
>>> so the solutions are either you use the Proxy2 library (which doesn't work
>>> with jdk9 yet) or we retrofit the interface InvocationHandler to take a
>>> supplementary Lookup object.
>>> regards,
>>> Rémi
>>>
>>> [1]
>>> http://docs.oracle.com/javase/7/docs/api/java/lang/invoke/MethodHandles.Lookup.html#findSpecial%28java.lang.Class,%20java.lang.String,%20java.lang.invoke.MethodType,%20java.lang.Class%29
>>> [2] https://github.com/forax/proxy2
>>
>> what is the problem under jdk9?
>
> Mostly the semantics of unsafe.defineAnonymousClass has changed so i have to investigate if i can workaround that :(

ah that, right :(

bye Jochen