question on exports to

[Jochen Theodorou]

On 01.06.2016 18:57, Peter Levart wrote:
[...]
>> Anyway... the groovy runtime would be almost something like java.base,
>> but instead of being like a root element, this one will have to sit in
>> the middle, because we depend on java as well.
>>
>>> If that is true, then perhaps there is a simpler solution that doesn't
>>> require modifying the exports of any module.
>>>
>>> Make your TheInvoker take another argument of type MethodHandles.Lookup:
>>>
>>> public class TheInvoker{
>>>      public static Object invoke(MethodHandles.Lookup lookup, Object
>>> receiver, String name, Object... args) throws Throwable {
>>>          Method m = receiver.getClass().getDeclaredMethod(name,
>>> toClass(args));
>>>          MethodHandle mh = lookup.unreflect(m).bindTo(receiver);
>>>          return mh.invokeWithArguments(args);
>>>      }
>>> ...
>>> }
>>>
>>> Then pass the appropriate lookup to it from where you call
>>> TheInvoker.invoke (from MyOtherLib):
>>>
>>> TheInvoker.invoke(MethodHandles.lookup(), receiver, "methodName",
>>> arguments...);
>>
>> receiver.getClass().getDeclaredMethod would fail, if I cannot access
>> the class of the receiver.
>
> No, for obtaining reflection objects you don't need language access
> rights. You need security permissions if security manager is installed,
> but that's independent of language access checks. Language access checks
> are performed when you call Method::invoke or Field::get, etc... or when
> you do Lookup::unreflect, but the later is performed against the "caller
> class" that is captured inside the Lookup object.

I was more thinking about modules here... well... now I am indeed 
confused. I thought I did see that module access rules are enforced, but 
I cannot find anything of that right now. So how does the module system 
enforce the module system at runtime? I mean if that is not the case, 
then why do I even need someething like Module#addReads? But the only 
part where I can see that happening right now is for setAccessible...


bye Jochen