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  1. JDK
  2. JDK-8260009

InstanceKlass::has_as_permitted_subclass() fails if subclass was redefined

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      b07

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        From: MRasmussen@perforce.com:

        Retransforming or redefining a sealed class can lead to a JVMTI_ERROR_FAILS_VERIFICATION, with Exception <a 'java/lang/IncompatibleClassChangeError'{0x00000000feb820a0}: class autotest.TransparentRectangle cannot inherit from sealed class autotest.Rectangle> (0x00000000feb820a0), even though the class actually does that.

        I've tried to investigate the reason, and from what I can tell, it boils down to the check in InstanceKlass::has_as_permitted_subclass.

        In jdk-16+27, this method always seems to take the Symbol branch (_constants->tag_at(cp_index).is_klass() is false).
        But for jdk-16+28, it takes the Klass branch after the classes are loaded, and from what I can tell the (k2 == k) comparison can then fail during the redefinition since the Klass stored in the _permitted_subclasses is not the same as the one being verified, as a new InstanceKlass is allocated for the stream parser.

        Unfortunately, I haven't been able to produce a small self-contained test example, but I can reliably reproduce it while developing JRebel (which utilizes class retransformation), but hopefully the above is at least helpful in finding the issue and fixing it.

        /Michael

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                Assignee:
                hseigel Harold Seigel
                Reporter:
                hseigel Harold Seigel
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