…as one of mine did, one thing you may try is to configure the CPU affinity of the OpenHAB processes.
This may be done by hand on a running process, using taskset(1):
# Restrict any java process(es) and their
# subprocesses (-a option) to CPUs 0 and 1 only
taskset -p -a 0x03 $(ps -axo pid,comm |grep java |cut -f1 -d' ')
Or it may be applied to the systemd service configuration, if you start OpenHAB that way, via the CPUAffinity option:
[Unit]
Description=openHAB - empowering the smart home
Documentation=https://www.openhab.org/docs/
Documentation=https://community.openhab.org
Wants=network-online.target
After=network-online.target
[Service]
Environment=OPENHAB_HOME=/usr/share/openhab
Environment=OPENHAB_CONF=/etc/openhab
Environment=OPENHAB_RUNTIME=/usr/share/openhab/runtime
Environment=OPENHAB_USERDATA=/var/lib/openhab
Environment=OPENHAB_LOGDIR=/var/log/openhab
Environment=OPENHAB_STARTMODE=daemon
EnvironmentFile=-/etc/default/openhab
User=openhab
Group=openhab
WorkingDirectory=/usr/share/openhab
ExecStart=/usr/share/openhab/runtime/bin/karaf ${OPENHAB_STARTMODE}
ExecStop=/usr/share/openhab/runtime/bin/karaf stop
SuccessExitStatus=0 143
RestartSec=5
Restart=on-failure
TimeoutStopSec=120
LimitNOFILE=102642
CPUAffinity=0,1
[Install]
WantedBy=multi-user.target
The examples above cause OpenHAB and any subprocesses to run only on CPUs 0 and 1. On a Raspberry Pi 4 B, for instance, that leaves two CPUs free for the operating system and other processes to use, hopefully addressing one of the possible causes of OpenHAB freezes.