PlayerDataConverter

[Howaner]

It converts your player data into player data with the correct uuid. (Example you want to switch your server to offline mode. With this plugin you can convert the online mode player data to offline mode player data, so your players will keep the inventory.)

Usage:

1. Download the source
   
2. Copy the PlayerDataConverter/ folder to your Plugins/ folder
   
3. Add the plugin to the settings.ini
   
4. Start / Reload the server
   

Github, Download

[xoft]

So what exactly does this plugin do that a server cannot do?

The server has two settings related to the playerdata storage - one setting allows you to turn on reading playerdata from old-style (name-based) storage, so if the server cannot find the UUID-based player data, it looks for the name-based one. The other setting does the same with offline UUID-based data.
Both are in settings.ini:

Code:

[PlayerData]
LoadOfflinePlayerData=1
LoadNamedPlayerData=1

[Howaner]

What is when the server is in online mode and you want to switch it to offline mode?

[xoft]

That's probably the only scenario not covered by the server.