docker stop command send SIGTERM to pid1 inside the container to let a chance to stop gracefully (https://www.ctl.io/developers/blog/post/gracefully-stopping-docker-containers/)
Unfortunatly some software ignore SIGTERM and need to be stopped by their own command (hello opendj)

To do so, in the Dockerfile, in the CMD, I use a script like this :
/thecommand/tostart/thesoftware/inbackground
trap "/thecommand/tostop/thesoftware" SIGTERM
while true; do sleep 1; done

so my script is run with PID1, docker stop sends SIGTERM, my script catch (trap) the signal, and run the command to stop gracefully