Whitelist.json

The whitelist.json is a server configuration file that stores the usernames of players who have been whitelisted on your server. This is only possible on multiplayer servers. To activate the whitelist, you will need to change the white-list value, in server.properties to true:  This will then only allow the named users to connect to your server. This is particularly useful if you want to run a private server.

As well as manually editing the file, you can use the command, if you are an operator.