VisualVM hanging on startup "computing description"

Question

I've got two remote servers, both running recent CentOS, both running recent Tomcat6, recent JDK6, and VisualVM 1.3.2.

ssh -X forwarding works on one server - I can start up VisualVM from that machine, it port forwards and runs fine - I see all the JVM processes running on that remote machine as 'local' in VVM.

ssh -X forwarding on the second machine - then running VisualVM - brings up an X windows with VVM in it, but it just shows one 'local' process - the VisualVM itself - and the lower right corner has a bouncing progress bar that says "computing description", and it never ends.

I can't find anything about this anywhere - anyone ever hit this? How do I get past this?

Answer 1

I experienced a similar issue - VisualVM hanging on "computing description", not displaying any local JVMs other than itself. I used "jps" to find all the JVMs running on the system. Used jstack to get the stacks of all those JVMs, including JVisualVM itself. What I found was happening, was that JVisualVM was trying to create an RMI connection to one of the target VMs, and that VM was hanging on the RMI connection attempt. In my case, the reason why it hanged was that I had the JVisualVM profiler attached to that JVM, but JVisualVM then died with a PermGen OOM. Parts of the profiler were still running in the target JVM, but were hanging due to lack of the profiler frontend; thus any attempt at class loading would hang, which would cause the incoming RMI from the new JVisualVM instance to hang also. Restarting the affected JVM resolved the issue.

Without any thread dumps, I can't say whether your issue was anything like mine or not; but if anyone gets this problem again, collecting thread dumps is a good idea. Whatever the root cause is, restarting all JVMs on your box (e.g. reboot) has a reasonable chance of solving it.