JVisualVM hangs when saving threaddumps (at least for large numbers of threads)

26c8b25b-162e-4ae7-b815-9569acd0c5d5

I've used VisualVM/JVisualVM for years but as long as I have been using it, it has every time and in every version frozen when I asked it to create a threaddump, specifically in the reload of the threaddump file that it created. I don't think it is the saving of the threaddump that is the problem. Because I can usually kill the VisualVM process (after the prerequisite (hope springs eternal) wait to see if the UI will unfreeze) and when reopening the VisualVM the threaddump does appear under the process node in the left panel. Trying to open that file will rehang VisualVM. But I can "Save As" to disk and load them near instantly in other ThreadDump analyzer tools.

I've tried upping the mem settings etc for Visual VM without success.

Typically this problem only starts to happen when the number of threads in the process (usually tomcat or tcserver) is in the 1000's plus. But just now it happened with a meager 900. With much smaller number of threads it has worked perfectly for me in the past.

When this does happen, not only does the VisualVM fail to respond, but the process is consuming 1 CPU at 100%.

I really like this tool and it would be great if this feature worked reliably.

Thanks