If we are using JOE for a JobScheduler then do we need to restart the JobScheduler every time after making changes to a job?
No, this is not necessary, JOE stores information about jobs, orders, etc. in XML files in the so-called "hot folder" (default location: ./config/live).
On Unix systems it may take up to a minute for changes made using JOE to become effective.
For a quick introduction to using JOE we recommend you take a look at our Quickstart Guide.