When you bulid MC server by the method: Running Minecraft Server On AWS.
You’ll find that when you close PUTTY session, the server should be closed at the same time. To avoid such a situation, you need to install a function named screen to your ubuntu server.
sudo apt-get install screen
run Minecraft server by:
screen java -Xmx1024M -Xms1024M -jar cauldron-1.7.10-1.1388.1.0-server.jar nogui
After then, your MC server will be running in a screen.
You could press Ctrl+A, and then press D to detach your screen back to original shell status.
Then you could
to find your screen session.
And the 1286 is the my screen ID.
When you log in AWS next time, you could
screen -r [screen ID]
to back to your screen which is running MC server.