RFR: 8328874: Class::forName0 should validate the class name length early [v12]

[Chen Liang]

On Fri, 29 Aug 2025 06:45:25 GMT, Guanqiang Han <ghan at openjdk.org> wrote:

>> Validate class name length immediately after GetStringUTFLength() in Class.forName0. This prevents potential issues caused by overly long class names before they reach later code that would reject them, throwing ClassNotFoundException early.
>
> Guanqiang Han has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update Class.java
>   
>   change overflow check

I recommend putting this PR on hold - 65535 encoded size for modified utf8 is significant enough for a cross-JDK utility. As @rose00 suggested, I think I will explore adding a check in ClassFile API, and sharing the check with here.

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PR Comment: https://git.openjdk.org/jdk/pull/26802#issuecomment-3249851989