Minecraft server on a Synology NAS

It had to happen - my son "requires" a Minecraft server! One of those things... I have installed mine on my Synology 415play following these instructions.
Disclaimer
These instructions worked for me, and may not work for you. They are "AS IS" and I accept NO RESPONSIBILITY WHATSOEVER for any loss or damage to your data or functionality. You have been warned.
Also: these are unsupported... if something doesn't work for you, you'll have to fix it yourself.

Prerequisite

Java

The "Java Manager" package must be installed. You can install it via the Package Manager, under "Utilities". 

Once the package is installed, the JVM will be located at

/var/packages/JavaManager/target/Java/bin/java

Terminal access

Enable terminal access via "Control Panel", "Terminal & SNMP". Then check "Enable SSH service" on port 22. Now you may need a SSH client, like PuTTY and connect to your NAS.

Manual installation

Create user

Create a user to run minecraft server as. To do so, I found easier to edit /etc/passwd and append the following line

minecraft:x:25565:100:Minecraft Server:/volume1/minecraft:/sbin/nologin

Create the server directory and download the server

I decided to put the server directory in /volume1/minecraft

mkdir /volume1/minecraft

then

 cd /volume1/minecraft  
 wget https://s3.amazonaws.com/Minecraft.Download/versions/1.8.3/minecraft_server.1.8.3.jar  

Note that the server version may change in the future. Check the latest version of the multiplayer server from Mojang's website

Create the start script

I am using a script to run the server. Use your favourite editor to create a file in /volume1/minecraft/run.sh with this content

 cd /volume1/minecraft
/var/packages/JavaManager/target/Java/bin/java -Xmx1024M -Xms1024M -jar /volume1/minecraft/minecraft_server.1.8.3.jar -o true -d64 nogui

then

chown minecraft:users run.sh
chmod 755 run.sh

Run the server

cd /volume1/minecraft
./run.sh

The first run will start the server and stop it straight away. In fact you need now to edit the eula.txt and "accept" as per instructions.
Re-run the script and the server should now start successfully. You can now try to connect your minecraft client.

Automatic start/stop

Create the file "/etc/init/minecraft.conf" with this content: 

description "start minecraft server"
author "smartrics"
console log
start on syno.share.ready and syno.network.ready

stop on runlevel [06]

setuid minecraft

pre-start script
    echo "netatalk start" || true
    date || true
    if [ ! -x /volume1/minecraft/run.sh ]; then
      stop; exit 1
    fi
end script

script
    exec /volume1/minecraft/run.sh
end script

post-stop script
    echo "minecraft server stop" || true
    date || true
    rm -f /var/run/minecraft.pid
end script

Then the server can simply be started/stopped with 

start minecraft
stop minecraft

and automatically be started at the next NAS reboot.

Check that service is running

If the server is running, this command

ps -w | grep minecraft

should show something similar to

 4735 minecraf  3768 S    /bin/sh /volume1/minecraft/run.sh
 4737 minecraf 1188m S    /var/packages/JavaManager/target/Java/bin/java -Xmx1024M -Xms1024M -jar /volume1/minecraft/minecraft_serv