1.12.2 start.bat.jar open server socket port on lobby demand

I want to create a start.bat.jar that opens lobby demand minigames.
I would like to know how multicraft sets the server ports without using server.properties.


example logical system
demand-server -> post {ip, port, players-limit} -> network.server.com
demand-server -> cmd: waiting for demand (limit: 48 players)
lobby-demand-gui -> connct network.ip (skywars) else network.open
lobby-demand -> network.open (skywars, 12);
demand-server return requests new json server socket {ip, port}

 

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