Bukkit

To set up the server for restarts please browse to your server's root folder and look for a "start" or "run" file.

Windows:
If you are using windows, it will most likely be a .bat file.
After you have located the file, open it and replace the contents of it with the following code, where

 java -Xmx3072M -Xms3072M -jar bukkit.jar 

represents your startup settings.

@echo off
SET BINDIR=%~dp0
CD /D "%BINDIR%"
:start
java -Xmx3072M -Xms3072M -jar bukkit.jar
goto start

Linux:
If your server is running linux the file will most likely be a .sh file. If so, please replace the file contents of it with the following code, where

 java -Xmx3072M -Xms3072M -jar bukkit.jar 

represents your startup settings.

 #!/bin/sh
BINDIR=$(dirname "$(readlink -fn "$0")")
cd "\$BINDIR"
while true
do
java -Xmx3072M -Xms3072M -jar bukkit.jar
echo "If you want to completely stop the server process now, press Ctrl+C before the time is up!"
echo "Rebooting in:"
for i in 5 4 3 2 1
do
echo "$i..."
sleep 1
done
echo "Rebooting now!"
done