8380391: Update java.smartcardio finalizer to use Cleaner

[bchristi-git]

This is a pull request to convert the finalizer in sun.security.smartcardio.CardImpl to use Cleaner instead. The relevant state is refactored into a Context object, in the standard fashion.

This change uses the recommended try/finally/reachabilityFence() technique to prevent races between the program thread and the Cleaner thread, per the Reference.reachabilityFence() API Note:

there is a race between the program thread running the method, and the cleanup thread running the Cleaner or finalizer. The cleanup thread could free a resource, followed by the program thread (still running the method) attempting to access the now-already-freed resource. Use of reachabilityFence can prevent this race by ensuring that the object remains strongly reachable.

See Reference.reachabilityFence() and java.lang.ref - Memory Visibility for details / background info.

The test creates a Card object, and allows it to be collected. This confirms that the new cleaning action does not hold onto the Owner ("this") object, per the Cleaner class API Note ("it is important that the object implementing the cleaning action does not hold references to the object").

I've tried to make the test similar to nearby JavaCard tests. I tried it on Windows using the latest JavaCard Simulator.

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Issue

• JDK-8380391: Update java.smartcardio finalizer to use Cleaner (Bug - P4)

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