Exception in thread "OH-eventexecutor-1"

Setup, Configuration and Use Runtime
1
  • Platform information:
    • Hardware: Pi4
    • OS: OpenHabian 3.0.2
    • openHAB version: 3.0.2

So today when I tried to toggle a switch and got ignored I went to look at the logs and found my openhab was stuck in some kind of “trance”. The web UI responded but nothing meaningful happened. Looking at my openhab log I found this moment in time when things got strange:

2021-06-18 04:01:45.590 [INFO ] [org.openhab.rule.NodeREDLog--       ] - S1 Motion Detected 2021-06-18T08:01:45.482Z
2021-06-18 05:32:03.937 [INFO ] [io.openhabcloud.internal.CloudClient] - Disconnected from the openHAB Cloud service (UUID = f2dcfd60-b4ea-4e15-ada0-10b5a42b8055, base URL = http://localhost:8080)
2021-06-18 05:33:01.337 [INFO ] [io.openhabcloud.internal.CloudClient] - Connected to the openHAB Cloud service (UUID = f2dcfd60-b4ea-4e15-ada0-10b5a42b8055, base URL = http://localhost:8080)
2021-06-18 06:50:01.380 [INFO ] [org.openhab.rule.31f37e7819         ] - vTimeOfDay: EARLY -> SCHOOL_PREP
2021-06-18 06:50:01.380 [INFO ] [org.openhab.rule.31f37e7819         ] - vTimeOfDay: EARLY -> SCHOOL_PREP
2021-06-18 06:51:00.177 [INFO ] [org.openhab.rule.31f37e7819         ] - vTimeOfDay: EARLY -> SCHOOL_PREP

That was strange because that rule shouldn’t do the same thing every minute. It seemed like Item vTimeOfDay wasn’t getting updates…

Then looking at my syslog I found this:

Jun 18 03:55:01 openHABianDevice CRON[18632]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)
Jun 18 03:56:15 openHABianDevice systemd[1]: Stopping Network Time Synchronization...
Jun 18 03:56:15 openHABianDevice systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 18 03:56:15 openHABianDevice systemd[1]: Stopped Network Time Synchronization.
Jun 18 03:56:15 openHABianDevice systemd[1]: Starting Network Time Synchronization...
Jun 18 03:56:15 openHABianDevice systemd[1]: Started Network Time Synchronization.
Jun 18 03:56:15 openHABianDevice systemd-timesyncd[18674]: Synchronized to time server for the first time 198.60.22.240:123 (0.debian.pool.ntp.org).
Jun 18 04:01:19 openHABianDevice systemd[1]: Stopping Network Time Synchronization...
Jun 18 04:01:20 openHABianDevice systemd[1]: systemd-timesyncd.service: Succeeded.
Jun 18 04:01:20 openHABianDevice systemd[1]: Stopped Network Time Synchronization.
Jun 18 04:01:20 openHABianDevice systemd[1]: Starting Network Time Synchronization...
Jun 18 04:01:20 openHABianDevice systemd[1]: Started Network Time Synchronization.
Jun 18 04:01:20 openHABianDevice systemd-timesyncd[18782]: Synchronized to time server for the first time 185.77.225.135:123 (0.debian.pool.ntp.org).
Jun 18 04:04:27 openHABianDevice karaf[667]: Exception in thread "OH-eventexecutor-1" Exception in thread "OH-eventexecutor-2" java.lang.NullPointerException
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:217)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Jun 18 04:04:27 openHABianDevice karaf[667]: Exception in thread "OH-eventexecutor-3" java.lang.NullPointerException
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Jun 18 04:04:27 openHABianDevice karaf[667]: Exception in thread "OH-eventexecutor-4" #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Jun 18 04:04:27 openHABianDevice karaf[667]: java.lang.NullPointerException
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Jun 18 04:04:27 openHABianDevice karaf[667]: #011at java.base/java.lang.Thread.run(Thread.java:834)

My syslog was 4G big full of these messages.

Not nice. How can I trust it if it might go into wonderland in the middle of the night without a way for me to see this happened?

Any clues of what might have happened here and how do I fix it or collect more data to fix it?

2

I would say that this points to a bigger issue with your system, possibly a failing SD card. At least it seems openHAB is not the only thing being affected, so the cause most likely lies outside of it.

3

Well, the syslog is normal, until the karaf message. NTP sync every x minutes is a common thing. I left the other lines in there to show everything seemed normal until that point.

Karaf is a component of OpenHAB’s tech stack. In OpenHAB’s log there is nothing at 04:04:27, only the issue at 05:32:03 evidences something went wrong in OpenHAB.

Finally, I don’t run on an SD card, but on a SSD hard drive. In any case, both are too new to already have failed.

If this is a common problem in OpenHABian, does someone have a way to monitor it and restart the service? A bash script of some kind?

4

Some extra info I’ve found in my logs. kern.log has this:

Jun 18 04:09:35 openHABianDevice kernel: [322042.913439] cgroup: fork rejected by pids controller in /system.slice/openhab.service

Googleing around this seems to be related to reaching a limit of tasks or threads. That would be strange, as I don’t have many Things/Items and I don’t run many rules.

Some extra info from my system:

openhabian@openHABianDevice:/var/log $ sudo systemctl status user.slice
[sudo] password for openhabian: 
● user.slice - User and Session Slice
   Loaded: loaded (/lib/systemd/system/user.slice; static; vendor preset: enabled)
   Active: active since Thu 2019-02-14 05:11:58 EST; 2 years 4 months ago
     Docs: man:systemd.special(7)
    Tasks: 8
   CGroup: /user.slice
           └─user-1000.slice
             ├─session-849.scope
             │ ├─25345 sshd: openhabian [priv]
             │ ├─25364 sshd: openhabian@pts/0
             │ ├─25365 -bash
             │ ├─25945 sudo systemctl status user.slice
             │ ├─25967 systemctl status user.slice
             │ └─25969 pager
             └─user@1000.service
               └─init.scope
                 ├─25349 /lib/systemd/systemd --user
                 └─25350 (sd-pam)

Anything looking too small there?

5

Might be, even though it seems excessive to sync every 5 minutes, but why would the service be restarted every time?

6

That is indeed a good question. It doesn’t happen in another linux box I have, but, that’s not Pi so I don’t know what this distribution is like. Yours doesn’t do this, right?

7

No, it has been running constantly since the last reboot almost 3 months ago

● systemd-timesyncd.service - Network Time Synchronization
   Loaded: loaded (/lib/systemd/system/systemd-timesyncd.service; enabled; vendor preset:   Drop-In: /usr/lib/systemd/system/systemd-timesyncd.service.d
           └─disable-with-time-daemon.conf
   Active: active (running) since Wed 2021-03-31 19:46:07 CEST; 2 months 19 days ago

But if you suspect too many tasks is run, what does systemctl status openhab show? Here’s mine for reference

● openhab.service - openHAB - empowering the smart home
   Loaded: loaded (/lib/systemd/system/openhab.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2021-06-11 13:42:03 CEST; 1 weeks 1 days ago
     Docs: https://www.openhab.org/docs/
           https://community.openhab.org
 Main PID: 659 (java)                                                                         
Tasks: 229 (limit: 4915)
   Memory: 1.2G
   CGroup: /system.slice/openhab.service
           └─659 /usr/lib/jvm/zulu11-ca-amd64//bin/java -XX:-UsePerfData -Dopenhab.home=/u

Is your number of tasks close to the limit?

8

This is what it shows now, and no it doesn’t seem close to the limit:

openhabian@openHABianDevice:~ $ sudo systemctl status openhab
[sudo] password for openhabian: 
● openhab.service - openHAB - empowering the smart home
   Loaded: loaded (/lib/systemd/system/openhab.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2021-06-18 20:30:38 EDT; 22h ago
     Docs: https://www.openhab.org/docs/
           https://community.openhab.org
 Main PID: 8485 (java)
    Tasks: 188 (limit: 3978)
   CGroup: /system.slice/openhab.service
           └─8485 /usr/bin/java -XX:-UsePerfData -Dopenhab.home=/usr/share/openhab -Dopenhab.conf=/etc/openhab -Dope

Jun 18 20:30:38 openHABianDevice systemd[1]: Started openHAB - empowering the smart home.

This was the first time it happened, I’ve been using OpenHAB for about 6 months now, but one time is enough to want to understand why and prevent.

9

Well, then your best bet is probably to monitor this value and see if it increases significantly over time. If it does, it might be a binding creating a lot of threads for some reason, so you should start looking into that. Unfortunately, about the only way to do this is by removing bindings one at a time until the problem disappears, then you at least know which binding causes this so you can look into it more.

10

Please open a bug on github so this can be tracked. It looks like something is causing a NPE to happen in the event handler. This may be resolved in 3.1 but it would be good to find out.

11

Good idea. I’ve added a crude log through cron, but should collect data to give an indication of when problems start to happen, if it happens again.

* * * * * echo `date --rfc-3339=seconds`" "`systemctl status openhab | grep Tasks` >> /var/log/openhab/task-count.log
12

Done

13

Hi,

I’ve seen an almost identical failure, just yesterday. System was unresponsive first thing in the morning, syslog full of NTP flapping, followed by an exception:

Hardware: Raspberry Pi 4 Model B Rev 1.2
OS: Raspbian GNU/Linux 10 (buster) 
JRE: OpenJDK Runtime Environment Zulu11.45+27-CA (build 11.0.10+9-LTS)
OH: 3.1.0 (Build)

syslog:

Nov 12 05:08:42 openhabian systemd-timesyncd[27480]: Synchronized to time server for the first time 194.0.5.123:123 (0.debian.pool.ntp.org).
Nov 12 05:08:45 openhabian rngd[398]: stats: bits received from HRNG source: 12280064
Nov 12 05:08:45 openhabian rngd[398]: stats: bits sent to kernel pool: 12235872
Nov 12 05:08:45 openhabian rngd[398]: stats: entropy added to kernel pool: 12235872
Nov 12 05:08:45 openhabian rngd[398]: stats: FIPS 140-2 successes: 614
Nov 12 05:08:45 openhabian rngd[398]: stats: FIPS 140-2 failures: 0
Nov 12 05:08:45 openhabian rngd[398]: stats: FIPS 140-2(2001-10-10) Monobit: 0
Nov 12 05:08:45 openhabian rngd[398]: stats: FIPS 140-2(2001-10-10) Poker: 0
Nov 12 05:08:45 openhabian rngd[398]: stats: FIPS 140-2(2001-10-10) Runs: 0
Nov 12 05:08:45 openhabian rngd[398]: stats: FIPS 140-2(2001-10-10) Long run: 0
Nov 12 05:08:45 openhabian rngd[398]: stats: FIPS 140-2(2001-10-10) Continuous run: 0
Nov 12 05:08:45 openhabian rngd[398]: stats: HRNG source speed: (min=243.705; avg=550.234; max=558.658)Kibits/s
Nov 12 05:08:45 openhabian rngd[398]: stats: FIPS tests speed: (min=11.279; avg=29.177; max=31.526)Mibits/s
Nov 12 05:08:45 openhabian rngd[398]: stats: Lowest ready-buffers level: 2
Nov 12 05:08:45 openhabian rngd[398]: stats: Entropy starvations: 0
Nov 12 05:08:45 openhabian rngd[398]: stats: Time spent starving for entropy: (min=0; avg=0.000; max=0)us
Nov 12 05:08:56 openhabian systemd[1]: Stopping Network Time Synchronization...
Nov 12 05:08:56 openhabian systemd[1]: systemd-timesyncd.service: Succeeded.
Nov 12 05:08:56 openhabian systemd[1]: Stopped Network Time Synchronization.
Nov 12 05:08:56 openhabian systemd[1]: Starting Network Time Synchronization...
Nov 12 05:08:56 openhabian systemd[1]: Started Network Time Synchronization.
Nov 12 05:09:01 openhabian systemd[1]: Stopping Network Time Synchronization...
Nov 12 05:09:01 openhabian systemd[1]: systemd-timesyncd.service: Succeeded.
Nov 12 05:09:01 openhabian systemd[1]: Stopped Network Time Synchronization.
Nov 12 05:09:01 openhabian systemd[1]: Starting Network Time Synchronization...
Nov 12 05:09:01 openhabian systemd[1]: Started Network Time Synchronization.
Nov 12 05:09:01 openhabian systemd-timesyncd[27536]: Synchronized to time server for the first time 194.0.5.123:123 (0.debian.pool.ntp.org).
Nov 12 05:09:31 openhabian systemd[1]: Stopping Network Time Synchronization...
Nov 12 05:09:31 openhabian systemd[1]: systemd-timesyncd.service: Succeeded.
Nov 12 05:09:31 openhabian systemd[1]: Stopped Network Time Synchronization.
Nov 12 05:09:31 openhabian systemd[1]: Starting Network Time Synchronization...
Nov 12 05:09:31 openhabian systemd[1]: Started Network Time Synchronization.
Nov 12 05:09:31 openhabian systemd-timesyncd[27575]: Synchronized to time server for the first time 194.0.5.123:123 (0.debian.pool.ntp.org).

// had been like this since midnight (when the log rotated)

Nov 12 05:35:01 openhabian CRON[29114]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-1" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:217)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-2" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-3" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-4" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-5" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-6" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-7" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-8" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-9" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-10" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-11" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-12" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-13" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-14" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-15" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-16" java.lang.NullPointerException
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.dequeue(LinkedBlockingQueue.java:214)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:435)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
Nov 12 05:35:27 openhabian karaf[18639]: #011at java.base/java.lang.Thread.run(Thread.java:834)
Nov 12 05:35:27 openhabian karaf[18639]: Exception in thread "OH-eventexecutor-17" java.lang.NullPointerException

I restarted openhab - sudo systemctl restart openhab and while it restarted eventually, it was very slow to do so - i.e. some rules etc didn’t appear to be working at first (motion-> lights), but seems to have been ok since.

Cheers
James