JEP 421: Deprecate Finalization for Removal

[tajila]

See https://openjdk.java.net/jeps/421

We propose to:

    Add a command-line option to disable finalization, so that no finalizers are ever scheduled by the GC to run, and
    Deprecate all finalizers, and finalization-related methods, in the standard Java API.

[tajila]

FYI @dmitripivkine

[tajila]

The option will be --finalization=[enabled|disabled] it will be enabled by default.

The effect of disabling finalization is as follows:

 * When a class is loaded into the JVM, the detection of a non-trivial finalize() method in the class is disabled. 
 This prevents creation of finalization-related data structures by various GCs. This also disables the upcall to 
Finalizer::register, which prevents finalization-eligible objects from ever appearing on the heap. 
FinalReference processing will therefore not be done, and objects' finalize() methods won't be called.

 * The finalizer thread is not created.

 * Calls to `System::runFinalization` and `Runtime::runFinalization` have no effect.

[tajila]

Its likely we will fail tests once this gets in the jdk18 repo due to the fact that we do not yet recognize the option

[tajila]

@JasonFengJ9 Can you take a look at this once it lands

[pshipton]

Its likely we will fail tests once this gets in the jdk18 repo due to the fact that we do not yet recognize the option

It depends how --finalization is processed. It may be done by the launcher and turned into a system property.

[pshipton]

Well we likely still need to add something to the Object.finalize() method.

[pshipton]

I see JVM_IsFinalizationEnabled() added.

[JasonFengJ9]

I see JVM_IsFinalizationEnabled() added.

Okay, will add it.

[keithc-ca]

See also #14114.

[tajila]

Can this be closed @JasonFengJ9 ?

[JasonFengJ9]

I am not aware any outstanding task required by this JEP.

Closing..