Convert current data to UUIDs

I have a plugin that stores playernames in the configuration file everytime they do /test

I've managed to make it so future data is stored as the UUID of the command sender instead of the username, but i've been having one issue that's been bugging me all day:

How can I convert the current usernames in that file to UUIDs?

So, here's an example:

Current file content:

Code:

claimed:
- Creeper_King310
- Notch

(Yes, there's a list in the config named "claimed")

What I want it to be converted to when the plugin is enabled:

Code:

claimed:
- 50ecc314-4b15-4118-852d-1b7620ea11df
- 069a79f4-44e9-4726-a5be-fca90e38aaf5

So, how would I go about doing this?

 

I tried doing this using UUIDFetcher:

Code:

    public void convertToUUID() {
    for (String name : getConfig().getStringList("claimed")) {
        UUIDFetcher fetcher = new UUIDFetcher(Arrays.asList(name));
        getConfig().getStringList("claimed").add(fetcher);
        }
    }

(I made it a void so I can just call convertToUUID(); onEnable).

But, i'm getting this error and a red line under "add": The method add(String) in the type List<String> is not applicable for the arguments (UUIDFetcher)

 

@MacDev You can use the OfflinePlayer getUniqueId method to get the true UUID (server must be in online mode but that's not a problem) of a Player if they have played before.

• Get the List
• Get the username
• Remove the username
• Add the UUID