This plugin could be useful, but you are calling the restart method from spigot, so you MUST have a ./start.sh script in order to make this plugin work. Better add a detailed description and mention above. The code from a task into a task ... is not really good, I would recommend you create scheduled tasks. If you have done all the above things I will review again to (I hope) 5 stars
I will clean up the code in the future, but I think that using the start.sh is superior to any other option because it allows for custom start parameters.