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Fix J9ClassHasIdentity flag assignment #23008

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Fix J9ClassHasIdentity flag assignment #23008

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4 changes: 2 additions & 2 deletions runtime/vm/createramclass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2406,8 +2406,8 @@ internalCreateRAMClassDone(J9VMThread *vmThread, J9ClassLoader *classLoader, J9C
}
#endif /* defined(J9VM_OPT_VALHALLA_FLATTENABLE_VALUE_TYPES) */
#endif /* defined(J9VM_OPT_VALHALLA_VALUE_TYPES) */
} else if (!(J9_IS_CLASSFILE_OR_ROMCLASS_VALUETYPE_VERSION(romClass) && J9ROMCLASS_IS_INTERFACE(romClass))) {
/* All classes before value type version are identity. */
} else if (!J9ROMCLASS_IS_VALUE(romClass) && !J9ROMCLASS_IS_INTERFACE(romClass)) {
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@theresa-m theresa-m Nov 25, 2025

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I think you can remove the interface check here. J9ROMCLASS_IS_VALUE is only true when an interface flag is not set.

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@AditiS11 AditiS11 Nov 26, 2025

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J9ROMCLASS_IS_VALUE is false for interfaces. If I remove the interface check, J9ROMCLASS_IS_VALUE will return false for interfaces and enters the else if block and sets J9ClassHasIdentity flag for interfaces too.

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@hangshao0 hangshao0 Nov 27, 2025 •
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In the original code, if Valhalla JDK is running on an older version of class file (e.g. Java 21), J9ClassHasIdentity is set on interface. With this change, J9ClassHasIdentity won't be set.

Have you checked the return value of java.lang.Class.isIdentity() with OpenJDK Valhalla build if given a interface compiled by Java 21 ?

/* All classes which are not value classes and are not interfaces are identity. */
classFlags |= J9ClassHasIdentity;
}
#if defined(J9VM_OPT_VALHALLA_FLATTENABLE_VALUE_TYPES)
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