On Dec 8, 2015, at 7:44 AM, David Holmes <david.hol...@oracle.com> wrote: > But thinking more on this approach this is simply not scalable. A > Cleaner per cleanable-class could result in hundreds of threads being > active!
That would indeed be awful. However, the scope of a Cleaner should not usually be a class. More typically it would be a subsystem, module, plugin, or some other sensible unit of sharing. I assume Peter's example had a class-scoped Cleaner for simplicity of presentation. A class-scoped Cleaner probably should be treated as a canonical anti-pattern for Cleaner usage; appropriate in rare circumstances, but usually a mistake. > What exactly are the advantages over finalization again? The same as PhantomReference-based cleanup vs finalization. - Performance (especially after JDK-8071507). - Semantic simplicity, avoiding the need to deal with resurrection of objects, and objects not needing to protect themselves from some kinds of post-cleanup misuse.
