RFR: 8303489: Add a test to verify classes in vmStruct have unique vtables [v2]

[Chris Plummer]

On Thu, 2 Mar 2023 23:32:47 GMT, Alex Menkov <amenkov at openjdk.org> wrote:

>> test/hotspot/jtreg/serviceability/sa/UniqueVtableTest.java line 85:
>> 
>>> 83:         int dupsFound = 0;
>>> 84:         // agent.getTypeDataBase() returns HotSpotTypeDataBase (extends BasicTypeDataBase)
>>> 85:         BasicTypeDataBase typeDB = (BasicTypeDataBase)(agent.getTypeDataBase());
>> 
>> I don't think the cast is needed.
>
> agent.getTypeDataBase() returns TypeDataBase, we need BasicTypeDataBase

Your comment seems to indicate otherwise, although I think what you meant is that the declared return type for agent.getTypeDataBase() is TypeDataBase, but it actually returns an object of type HotSpotTypeDataBase, which is a subclass of BasicTypeDataBase. You should make that more clear.

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PR: https://git.openjdk.org/jdk/pull/12820