Prison, on a whole, is unable to be reloaded. It is always safest to restart the server under most situations, otherwise corruption may occur.
That said, placeholders are currently the only exception to that “rule”. By issuing the command
\prison reload placeholders it will regenerate the placeholder mappings and reregister with any of the active placeholder plugins that prison is integrated with, such as PlaceholderAPI. Reloading the placeholders is safe to run at any time.
A couple of examples when you would need to use the reload command for placeholders:
/prison reload autofeaturesReloads all of the auto features settings, including reregistering all of the event listeners that are related to block break events.
/prison reload localesReloads the language files.
/prison reload placeholdersRegenerates all the placeholder mappings and reregisters them with the supported placeholder plugins.
Use the command
/prison reload for the list of subcommands.
END of the command INFO