Everyone, Please take a look at new version of the fix.
http://cr.openjdk.java.net/~dsamersoff/JDK-8059036/webrev.10/ Changes (to previous version) are in Finalizer.java and diagnosticCommand.cpp This version copy data from Map.Entry<> to array of FinalizerHistogramEntry instances then, VM prints content of this array. -Dmitry On 2015-05-28 21:06, Mandy Chung wrote: > > On 05/28/2015 07:35 AM, Peter Levart wrote: >> Hi Mandy, >> >> On 05/27/2015 03:32 PM, Mandy Chung wrote: >>> Taking it further - is it simpler to return String[] of all >>> classnames including the duplicated ones and have the VM do the >>> count? Are you concerned with the size of the String[]? >> >> Yes, the histogram is much smaller than the list of all instances. >> There can be millions of instances waiting in finalizer queue, but >> only a few distinct classes. > > Do you happen to know what libraries are the major contributors to these > millions of finalizers? > > It has been strongly recommended to avoid finalizers (see Effective Java > Item 7). I'm not surprised that existing code is still using > finalizers while we should really encourage them to migrate away from it. > >> What could be done in Java to simplify things in native code but still >> not format the output is to convert the array of Map.Entry(s) into an >> Object[] array of alternating {String, int[], String, int[], .... } >> >> Would this simplify native code for the price of a little extra work >> in Java? The sizes of old and new arrays are not big (# of distinct >> classes of finalizable objects in the queue). > > I also prefer writing in Java and writing less native code (much > simplified). It's an interface that we have to agree upon and keep it > simple. Having the returned Object[] as alternate String and int[] is a > reasonable compromise. > > ReferenceQueue.java - you can move @SuppressWarning from the method to > just the field variable "rn" > @SuppressWarnings("unchecked") > Reference<? extends T> rn = r.next; > > Finalizer.java > It's better to rename printFinalizationQueue as it inspects the > finalizer reference queue (maybe getFinalizerHistogram?). Can you move > this method to the end of this class and add the comment saying that > this is invoked by VM for jcmd -finalizerinfo support and @return to > describe the returned content. I also think you can remove > @SuppressWarnings for this method. > > Mandy -- Dmitry Samersoff Oracle Java development team, Saint Petersburg, Russia * I would love to change the world, but they won't give me the sources.
