My command manager class is throwing null pointer exception, why?

So I'v done a lot of plugin developing, but never tackled commands for some reason. This is my code

Code:

public class Main extends JavaPlugin {
    private static Main plugin;
    private CommandManager commandMgr;

    @Override
    public void onEnable() {
        // Declaring variables
        plugin = this;

        // Configuration version handler
        ConfigManager.loadConfig();

        if (!getDescription().getVersion().equals(this.getConfig().getString("version"))) {
            plugin.saveResource("config.yml", true);
            getLogger().info("Config version does not match plugin version, overwriting config, please ensure you adjust appropriately...");
            getLogger().info("Plugin version: [" + getDescription().getVersion() + "] Config version: [" + getConfig().getString("version") + "]");
        }

        // Create recipes required for plugin
        Utilities.createRecipes();

        // Start reading events of the server
        registerEvents();

        // Start Cooldown mechanisms
        Cooldowns.CooldownTimer();

        commandMgr = new CommandManager(this);
        getCommand("raidaccept").setExecutor(commandMgr);
 
    }
}

And this is the CommandManager class

Code:

public class CommandManager implements CommandExecutor {

    private final Main plugin;
    public CommandManager(Main para) {
        this.plugin = para;
    }

    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
        if (command.getName().equalsIgnoreCase("raidaccept")) {
            sender.sendMessage(ChatColor.GOLD + "Raid accepted");
            for (String var : args) {
                sender.sendMessage(ChatColor.GOLD + "String Args: " + var);
            }
            return true;
        }
        return false;
    }
}

The console shows this

[07-09-2019 21:28:50] java.lang.NullPointerException: null

On line 45, which is.

Code:

        commandMgr = new CommandManager(this); 

In the main class.

is 'this' null? and why would it be?

I was missing it out of plugins.yml

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

@Benyon Unless you register multiple commands in the same class, you won't need to check if the command name is "raidaccept".

'this' can never be null; it would be impossible to call a method from something that is null.

Does that mean that this is solved?