RFR: 8256867: Classes with empty PermittedSubclasses attribute cannot be extended

Mandy Chung mchung at openjdk.java.net
Tue Dec 8 00:16:12 UTC 2020

On Mon, 7 Dec 2020 19:51:38 GMT, Harold Seigel <hseigel at openjdk.org> wrote:

> Please review this fix for JDK-8256867.  This change no longer throws a ClassFormatError exception when loading a class whose PermittedSubclasses attribute is empty (contains no classes).  Instead, the class is treated as a sealed class which cannot be extended nor implemented.  This new behavior conforms to the JVM Spec.
> This change required changing Class.permittedSubclasses() to return an empty array for classes with empty PermittedSubclasses attributes, and to return null for non-sealed classes.
> This fix was tested with Mach5 tiers 1-2 on Linux, MacOS, and Windows, and tiers 3-5 on Linux x64.
> Thanks, Harold

Other changes look okay except the spec of `Class::getPermittedSubclasses`


PR: https://git.openjdk.java.net/jdk/pull/1675

More information about the compiler-dev mailing list