JDK-8256867 : Classes with empty PermittedSubclasses attribute cannot be extended
  • Type: Bug
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 16
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2020-11-23
  • Updated: 2020-12-14
  • Resolved: 2020-12-09
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JDK 16
16 b28Fixed
Related Reports
CSR :  
JDK-8257861 - Class::getPermittedSubclasses returns null on non-sealed class or interface
Relates :  
JDK-8246777 - JVMS changes for Sealed Classes (Second Preview)
Description
Currently, if the number_of_classes field in the PermittedSubclasses attribute is zero then the JVM throws a ClassFormatError exception.  Instead, no exception should be thrown and the class cannot be extended.
Comments
Changeset: d33a689b Author: Harold Seigel <hseigel@openjdk.org> Date: 2020-12-09 19:07:11 +0000 URL: https://git.openjdk.java.net/jdk/commit/d33a689b
09-12-2020
As part of this change, the Class.getPermittedSubclasses() will be changed to return null for non-sealed classes. This will also fix isSealed behavior after JDK-8246778 in some less common, but not rare cases. So I'd re-evaluate to: ILW=MMM=P3 for the state that will exist after the presumed integration of JDK-8246778.
03-12-2020
ILW = MLM = P4
24-11-2020