In systemd-resolved hosts with no DNS customizations, the docker driver
DNS setting should be compared to /run/systemd/resolve/resolv.conf while
exec/java drivers should be compared to /etc/resolv.conf.
When system-resolved is enabled, /etc/resolv.conf is a stub that points
to 127.0.0.53. Docker avoids this stub because this address isn't
accessible from the container. The exec/java drivers that don't create
network isolations use the stub though in the default configuration.
