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JDK 19: Constant class entries ending in ‘/’

Prior to JDK 19, the JVM is loading classes (1) whose class file major version is <49, i.e., before JDK 1.5, and (2) the class’s name ends with a ‘/’. This violates section 4.2.1 of the JVM specification and is addressed in JDK 19. In JDK 19, the JVM is throwing, for such classes, a ClassFormatError exception as it already does with newer classes (JDK 1.5+). Given that this issue affects only pre-JDK 1.5 classes, the compatibility risk is expected to be very low.

Call to Action

No action is required unless codebase using pre-JDK 1.5 classes are involved. Questions and proper feedback should be sent to the hotspot-dev mailing list.