8161129 Unsafe::getUnsafe should allow the platform class loader to access it

[Remi Forax]

Hi Paul,

----- Mail original -----
> De: "Paul Sandoz" <paul.sandoz at oracle.com>
> À: "Core-Libs-Dev" <core-libs-dev at openjdk.java.net>
> Envoyé: Lundi 18 Juillet 2016 18:06:44
> Objet: 8161129 Unsafe::getUnsafe should allow the platform class loader to	access it
> 
> Hi,
> 
> Please review the patch below.
> 

[...]

> I also took the opportunity to hide the “theInternalUnsafe” field in the
> sun.misc.Unsafe. That just avoids any futile attempts to obtain the field’s
> value after which any reflective access on that value will fail.

I see 3 good reasons to not do that,
- as you said it is futile to try to get a reference to jdk.internal.misc.Unsafe because you will never be able to call a method on it.
- the code you add contains a string that reference a field name which is erro prone when doing a refactoring
- jdk.internal.misc.Unsafe is stored in static fields of a lot of exported classes, so why trying to 'protect' only sun.misc.Unsafe. 

> 
> Paul.

Rémi


> diff -r 4f5f82c457af src/jdk.unsupported/share/classes/sun/misc/Unsafe.java
> --- a/src/jdk.unsupported/share/classes/sun/misc/Unsafe.java	Mon Jul 18
> 13:13:52 2016 +0800
> +++ b/src/jdk.unsupported/share/classes/sun/misc/Unsafe.java	Mon Jul 18
> 17:50:20 2016 +0200
> @@ -56,6 +56,7 @@
> 
>      static {
>          Reflection.registerMethodsToFilter(Unsafe.class, "getUnsafe");
> +        Reflection.registerFieldsToFilter(Unsafe.class,
> "theInternalUnsafe");
>      }
> 
>      private Unsafe() {}
>