On Tue, 22 Apr 2025 23:55:54 GMT, Chen Liang <li...@openjdk.org> wrote:
> In the future value objects JEP, class files must have one of ACC_IDENTITY > (now ACC_SUPER), ACC_ABSTRACT, and ACC_FINAL bits set, otherwise they are > rejected. The current default flag has none of these bits set, meaning that > it will not be suitable in the future. Currently, most class file generation > in the JDK explicitly set ACC_SUPER for compatibility; we should also set > this bit in the default flags, despite being no-op, in anticipation of future > compatibility. > > The API specifications of ClassBuilder and AccessFlags already state that an > unspecified default flag for class builders are chosen, so changing this flag > should be fine without extra specification changes. Currently, most of the sites in JDK and community bytecode generation that specify access flags for a class provide an explicit `ACC_SUPER`; it is always effectively enabled since Java 8 even when it is not set. The alternative is in valhalla, we choose a different default when the flag is default and withVersion is called. I think that is overcomplicated, and we should better just set the consensual `ACC_SUPER` flag even if the behavior has already been on by default. ------------- PR Comment: https://git.openjdk.org/jdk/pull/24808#issuecomment-2830678906
