RFR 9: 8138696 : java.lang.ref.Cleaner - an easy to use alternative to finalization
brian.goetz at oracle.com
Wed Oct 14 13:17:02 UTC 2015
> Finally, how important is it to be able to unregister a cleaner? In
> all the years we've had sun.misc.Cleaner that capability has never
> been needed, and leaving it out would simplify the API.
I see this as having two big potential benefits (I'll let Roger confirm
whether the implementation provides both):
- Resource release for finalizable objects is generally coded in two
places; in the explicit close() / release() method, which we hope people
will use, and in the finalizer, in case the object is collected without
being closed. Having two ways to express the same action is
error-prone; if there's one definition of "release the
houn^H^H^H^Hresources" then they can't get out of sync.
This requires an atomic means to say "unregister the cleaner, and, if
its not yet been run, run it now".
- If you can unregister the cleaner on the happy path (where the user
explicitly closes the object ), then all the enqueue / reference
processing / finalization work can be optimized away.
More information about the core-libs-dev