PlayerConfigAPI

PlayerConfigAPI pca = new PlayerConfigAPI(this);
pca.exists(player);//Returns true if player config exists, else false
pca.createConfig(player);//Creates a config for the player
pca.set(player, configPath, value);//Sets a configPath to a value
pca.getString(player, configPath);////Returns String from configPath
pca.getInteger(player, configPath);//Returns int from configPath
pca.getBoolean(player, configPath);//Returns boolean from configPath

//This plugin example creates a config for each player upon joining

PlayerConfigAPI pca = new PlayerConfigAPI(this);

public void onEnable() {
    getServer().getPluginManager().registerEvents(this, this);
}

@EventHandler
public void onPlayerJoin(PlayerJoinEvent e) {
    Player p = e.getPlayer();
    if (!pca.exists(p))
    {
        pca.createConfig(e.getPlayer());
        pca.set(p, "lastName", p.getName());
    }
}