I need advice on tracking down a problem I've had since I installed Ubuntu fairly recently.
Background: In this question, we worked through issues with my graphics card and driver. We made the PC useable but it seems something else was a co-existing issue.
I think the problem is snaps which, when they crash, seem to take other things with them. Right now I have a Java-based app (Netbeans) that has stalled out. The System Monitor tries to start but just gives up.
I tried sudo killall java. No such processes apparently.
I tried xkill a few times but it ignored me. I tried sudo xkill but that did nothing too.
I've googled hard and tried a bunch of stuff without success.
I tried pkill -f 'netbeans' from this answer. My terminal instance just sat there waiting until I did a CNTL+C after a few minutes of nothing happening.
I tried following this answer: I opened a new terminal and ran ps aux | grep netbeans which I'm still waiting on.
I know it looks like Netbeans is at fault here but I've had Firefox bork things in the same way where the tools I'd use to recover hang too.
That's not the only weirdness this time. I closed LMMS last night but there is a process for LMMs still running that ignores sudo kill <pid>.
As a result, I'm currently working around a fully modal rectangle in the middle of my display.
These sorts of stall problems happen a few times a week although this is by far the most irritating. I shall probably have to reboot as I am out of ideas.
What do I need to do in order to identify the cause?
For bonus points, I'd love to learn how to recover from this next time.
Update: I tried logging out (success) and logging in again but it hung on a black screen. I pressed the power button to trigger a shutdown. It hung during shutdown so I forced a power off and then booted again.
