RFR: 8359053: Implement JEP 504 - Remove the Applet API [v6]

[Sergey Bylokhov]

On Thu, 12 Jun 2025 21:45:50 GMT, Phil Race <prr at openjdk.org> wrote:

>> src/java.desktop/share/classes/javax/imageio/spi/IIORegistry.java line 113:
>> 
>>> 111:      * registry functions.
>>> 112:      *
>>> 113:      * <p> Each {@code ThreadGroup} will receive its own instance.
>> 
>> Note that this new specification is not tied to AppContext. Do we still want to support ThreadGroup sandboxing even if AppContext will be removed? Can we drop it now, since current spec clearly tied to applets and AppContext usage?
>
> AppContext is really a ThreadGroup so it will behave as specified.
> Changing this needs to be done in a separate follow-up bug likely with a CSR-specific to ImageIO, removing the ThreadGroup support.
> Not in this PR. I submitted  https://bugs.openjdk.org/browse/JDK-8359391

I would like to confirm that we treat ThreadGroup based sandboxing as equivalent to AppContext based sandboxing. There are a few places where we still use ThreadGroup instead of AppContext, and I believe we can drop that usage at the same time AppContext is removed, even if the specification includes statements like "Each {@code ThreadGroup} will receive its own instance." - correct?

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/25698#discussion_r2143782847