$ docker run -p 8080:8080 my-app:v10
sh: 1: exec: /opt/my/bin/start-app.sh: not found

$ docker run -p 8080:8080 -it my-app:v10 bash
root@a03420ab2360:/opt/my# exec
root@a03420ab2360:/opt/my# ls /opt/my/
bin/    config/ lib/    log/    
root@a03420ab2360:/opt/my# ls /opt/my/bin/
start-app.sh

$ tail Dockerfile 
...
CMD ["exec /opt/my/bin/start-app.sh"]

CMD ["exec /opt/my/bin/start-app.sh"]

ENTRYPOINT ["sh", "-c"]
CMD ["exec /opt/my/bin/start-app.sh"]