JoinJail was made to create a sort of password protected server. We found that running a Minecraft server in offline mode made our whitelist not work properly. So I made this mod.
This mod generates a bedrock jail / holding place very very very far away from spawn. The only way to leave the jail is by using the set password. If a user dies in the jail they will spawn outside the jail but the first tick after spawning they will be back in the jail.