Lost ability to open web browser

Setup, Configuration and Use Beginners
1

So sometime today my data dropped off of Grafana and then I lost my access to the web browser. I looked at some post and did this command

systemcl status openhab2

and get the following…

[19:49:40] openhabian@openhab:~$ systemctl status openhab2
● openhab2.service - openHAB 2 - empowering the smart home
Loaded: loaded (/usr/lib/systemd/system/openhab2.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2020-04-08 17:16:05 MDT; 1 weeks 1 days ago
Docs: https://www.openhab.org/docs/
https://community.openhab.org
Main PID: 671 (java)
Tasks: 3015 (limit: 4915)
Memory: 1008.1M
CGroup: /system.slice/openhab2.service
└─671 /usr/bin/java -Dopenhab.home=/usr/share/openhab2 -Dopenhab.conf=/etc/openhab2 -Dopenhab.runtime=/usr/share/openhab2

Apr 16 14:38:39 openhab karaf[671]: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
Apr 16 14:38:39 openhab karaf[671]: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
Apr 16 14:38:39 openhab karaf[671]: at java.lang.Thread.run(Thread.java:748)
Apr 16 14:38:39 openhab karaf[671]: java.lang.NullPointerException
Apr 16 14:38:39 openhab karaf[671]: at java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:213)
Apr 16 14:38:39 openhab karaf[671]: at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:444)
Apr 16 14:38:39 openhab karaf[671]: at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
Apr 16 14:38:39 openhab karaf[671]: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
Apr 16 14:38:39 openhab karaf[671]: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
Apr 16 14:38:39 openhab karaf[671]: at java.lang.Thread.run(Thread.java:748)

I see that maybe java.lang.NULLPointerException is out of place ?

2

I shut down the Pi and re-started and things seems to be ok now but would still like to understand what happened.

3

How did you shut down the pi? If by turning power off then please do that only as a last resort. To shutdown use sudo shutdown and for restarting OH, which is generally all that is needed use sudo systemctl restart openhab2.

Are you using an SD card? If so, and this continues then it may be the signs of a corrupt SD card especially if you have frequent power issues.

Do you use a lot of rules in your automation setup? If so there are a few things that might can help as your limited to 5 (I think) treads running at the same time.

4

There is not enough data here to begin to diagnose what happened unfortunately. The biggest thing is we do not have the actual exception that occurred. What you’ve posted is just the bottom part of a stack trace. The full exception might be in the syslog.

I recommend letting it run. When/if the problem occurs again look through /var/log/syslog or execute sudo journalctl to see the syslog. The full error should appear there.

Do you see any errors in openhab.log?

5

All so my stupidity caused the problem or at least I think that is what caused the problem.

I was playing around with my items and I changed the names of some of them, however the names were not changed in some of the persistence/rules and therefore in grafana (grafana could not find the items).

My guess is OH just gave up trying to make sense of things ?