Multiple instances of the same cron job on web server [closed]

I was wondering what would happen if i create a cron job that needs to be executed every minute and once the execution starts the code is such that it takes more than one minute to complete. In this case will the execution of the previous cron job get terminated after one minute and then the new instance of that cron job will start executing or will there be two instances of the same cron job running on the server?