On 2015-05-21 02:07, Mandy Chung wrote: > >> On May 19, 2015, at 11:51 PM, Dmitry Samersoff >> <dmitry.samers...@oracle.com <mailto:dmitry.samers...@oracle.com>> wrote: >> >> Other alternatives could be to do all hashing/sorting/printing on native >> layer i.e. implement printFinalizationQueue inside VM. >> >> Both options has pros and cons - Java based solution requires less JNI >> calls and better readable but takes more memory. >> >> It might be better to return an array of Map.Entry<String, int[]> >> objects to VM rather than one huge string. > > The output and formatting should be done by jcmd.
done. > What you really need > to get a peek on the finalizer queue and print the histogram. The VM > has the heap histogram implementation. Have you considered leveraging > that? > > 5: 1012 40480 java.lang.ref.Finalizer One of previous versions count total a number of instances registered for finalization but then we decided that number of unreachable instances awaiting finalization has more value for customer. > You can find the registered Finalizer instances. The downside is that > icmd -finalizerinfo stops the world. I think it’s not unreasonable for > this diagnostic command to be expensive like -heap command. Current implementation is lock-free and don't stop the world, we decided to make it less expensive at the cost of less accurate results. -Dmitry -- Dmitry Samersoff Oracle Java development team, Saint Petersburg, Russia * I would love to change the world, but they won't give me the sources.
