RFR: 8365292: Remove javax.imageio.spi.ServiceRegistry.finalize()

[Phil Race]

On Tue, 12 Aug 2025 19:32:33 GMT, Phil Race <prr at openjdk.org> wrote:

> Remove javax.imageio.spi.ServiceRegistry.finalize() since it is deprecated for removal.
> The impact of this should be minimal. The IIORegistry will now be a singleton - which it already was 
> in practice since Applets are no longer supported. Since it is a singleton, it will persist for the life
> of the VM, so will never be garbage collected.
> A test that verifies one per-AppContext is now obsolete, and is deleted, and there's no good reason to make it a negative test, since in due course AppContext itself will be deleted and is un-used today except in tests.
> 
> Since JDK 9, ServiceRegistry has supported only Image I/O specified providers, and since the IIORegistry does this,
> in practice there is very little reason for an application to create instances or subclasses of it.
> And even if they do, typically like IIORegistry, they be used for the life time of the application.
> And if they are collected, without calling ServiceRegistry.deregisterAll() there may be no impact,
> since only providers that implement RegisterableService will be affected.
> 
> See the JBS issue for all the details.

src/java.desktop/share/classes/javax/imageio/spi/ServiceRegistry.java line 82:

> 80:  * <p> An application may customize the contents of a registry as it
> 81:  * sees fit.
> 82:  *

Removing the above text is not related to finalization, but the text is meaningless since the SecurityManager was permanently disabled, so I will take this opportunity to remove it.

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

PR Review Comment: https://git.openjdk.org/jdk/pull/26752#discussion_r2270981436