How does BungeeCord process console input?

Looking at the BungeeCordLauncher.java class, located under BungeeCord/bootstrap/src/main/java/net/md_5/bungee/BungeeCordLauncher.java

I can't seem to find anything that would hinder my direct input into the main process, is anyone familiar on how the process is started/running?

I'm able to do this for Spigot and other server types, so it must be...

How does BungeeCord process console input?