On Tue, 9 Nov 2021 00:31:36 GMT, Brent Christian <bchri...@openjdk.org> wrote:
>> A cleaner can/should be shared within some scope and purpose, in this case >> the example class . >> Each cleaner has a dedicated Thread so its not a lightweight object and >> should not be proliferated. >> (Loom may be able to use Virtual Threads). >> >> The reasons to not share are a Cleaner are based on possible interference >> between the cleanup callbacks. >> If they share a thread and are non-trivial, it might slow other cleaners. If >> the cleaner is created and shared >> for a particular purpose it will share the thread resource and still be >> efficient. > > The new example Cleaner instance _is_ shared, though on a pretty small scale > (just among instances of CleaningExample). A demonstration of larger scale > sharing of a Cleaner instance would be out of scope for this example. Let me add, why I have raised this issue. I was going to migrate some older code which uses the `finalize()` method to the `Cleaner` mechanism. New it it, there seemed to be two pitfalls: 1. Understanding the whole "don't capture an instance reference in your state object" 2. Copying the example (which was in a non-working state, due to pseudo code) and making it work for me With the improvement suggestions, I was trying help people who *only* read the code sample (many do), to become aware of 1. and help them getting going with 2, simply because it's something they can copy and run. ------------- PR: https://git.openjdk.java.net/jdk/pull/6076
