IllegalAccessError with --patch-module

[Alan Bateman]

On 06/01/2021 19:15, Thiago Henrique Hupner wrote:
> Hi!
>
> I've noticed something strange, but I don't know if it is a bug:
> If we have two jars:
> module.a with the class com.foo.Bar
> module.b with the classes com.foo.Bar and com.foo.Main.
>
> Running:
> java -p module-a.jar --patch-module=module.a=module-b.jar -m
> module.a/com.foo.Main
>
> it throws:
> Error: Unable to load main class com.foo.Main in module module.a
>          java.lang.IllegalAccessError: superclass access check failed: class
> com.foo.Main (in module module.a) cannot access class java.lang.Object (in
> module java.base) because module java.base does not export java.lang to
> module module.a
>
> Even with --add-exports=java.base/java.lang=module.a it doesn't work.
>
> Is this a bug? I have a real usage where the main class is the "patched"
> module to override the com.foo.Bar.
>
I'm not aware of any issues in this area. Can you create a test case as 
that might be easier to discuss? (I'm guessing the module names aren't 
"module.a" and "module.b" as that won't compile. Also I would expect 
this type of patching to emit a warning that the module-info.class in 
module-b.jar is ignored).

-Alan