Minecraft server 1.7.9 crash

Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...Launch 1.7.9 and do multiplayer click on a survival server and it crashes
3. ...