On 12/04/2015 10:58 PM, Mandy Chung wrote:
"It is possible to create a phantom reference with a null queue, but such a reference is completely useless: Its get method will always return null and, since it does not have a queue, it will never be enqueued.” The puzzling part to me is why PhantomReference accepts null ReferenceQueue. I can’t evaluate how high of the source incompatibility risk if we fixed it but I may propose that in a future release until I have cycle. Mandy
Well, it is not completely useless for PhantomReference to accept null ReferenceQueue. It's sometimes useful to have a common subtype of PhantomReference where most of instances perform a function of PhantomReference, but some instances are just there to provide the "glue" in the data structure. See the implementation of java.lang.ref.Cleaner and it's "root" nodes of a doubly-linked list ;-)
Regards, Peter
