Now in the new updates, you can do /spawnpoint @a for private servers. All joiners of the server must be online for that to work. But also as an alternative, you can use /setworldspawn. But this sets the spawn around nearby chunks, not a specific coordinate.
Private Mod Note
Rollback Post to RevisionRollBack
Hi there! I see you're bored. Don't worry! Come and visit us!
Log into Minecraft, click Multiplayer, click Add Server, name it 'Universia', and ENTER THE IP BELOW!