On Mon, 7 Dec 2020 21:29:23 GMT, Lois Foltan <lfol...@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 > > src/hotspot/share/prims/jvm.cpp line 2130: > >> 2128: JvmtiVMObjectAllocEventCollector oam; >> 2129: Array<u2>* subclasses = ik->permitted_subclasses(); >> 2130: int length = subclasses == NULL ? 0 : subclasses->length(); > > Minor comment - you don't really need the check of subclasses == NULL here > since subclasses will never be NULL. You could just assign length to > subclasses->length(); +1. is_sealed returns true iff `_permitted_subclasses != NULL` ------------- PR: https://git.openjdk.java.net/jdk/pull/1675