The custom.jar for Snapshot 14w20b doesn't work on my Server

Put the summary of the bug you're having here

What I expected to happen was...:
For me to be able to successfully join my server with the custom.jar set to the latest snapshop (14w20b).

What actually happened was...:
The server dashboard kept on restarting, and not actually being online.

Steps to Reproduce:
1. It is quite simple, you just have to name the jar file custom.jar, and then put it into your server database.
2. When you boot the server up with the custom.jar, it just doesn't turn on.