SimpleCommand

org.bukkit.command.Command
  └── org.mineacademy.fo.command.SimpleCommand

public class ReloadCommand extends SimpleCommand {
    
    public ReloadCommand() {
        super("reload|rl");
        
        setDescription("Reloads the plugin configuration");
        setUsage("[config|data]");
        setPermission("myplugin.command.reload");
        setMinArguments(0);
    }
    
    @Override
    protected void onCommand() {
        tellSuccess("Plugin reloaded successfully!");
    }
}

// Register a command
ReloadCommand reloadCmd = new ReloadCommand();
reloadCmd.register();

// Later unregister it
reloadCmd.unregister();

@Override
protected void onCommand() {
    if (args.length == 0) {
        tell("Usage: /mycommand <player>");
        return;
    }
    
    Player target = findPlayer(args[0]);
    tell("Found player: " + target.getName());
}

@Override
protected void onCommand() {
    checkConsole(); // Only players can run this
    
    Player player = getPlayer();
    // Do something with player...
}

checkBoolean(player.getHealth() > 0, "You must be alive to use this!");

Player target = findPlayerOrSelf(0); // /heal or /heal <player>
tellSuccess("Healed " + target.getName());

findOfflinePlayer(args[0], offlinePlayer -> {
    tell("Player last played: " + offlinePlayer.getLastPlayed());
});

GameMode mode = findEnum(GameMode.class, args[0], 
    "Invalid game mode {enum}! Available: {available}");

int amount = findNumber(0, 1, 64, "Amount must be between {min} and {max}!");

if (!player.hasPermission("special.feature")) {
    returnTell("You need special permission!");
    // Code here never executes
}

public MyCommand() {
    super("mycommand");
    setCooldown(30, TimeUnit.SECONDS);
}

@Override
protected List<String> tabComplete() {
    if (args.length == 1)
        return completeLastWord("create", "delete", "list");
    
    if (args.length == 2 && args[0].equals("delete"))
        return completeLastWord(getArenaNames());
    
    return NO_COMPLETE; // Disable tab completion
}

String message = joinArgs(1); // Join all args after first one
tell("Message: " + message);

public class TeleportCommand extends SimpleCommand {
    
    public TeleportCommand() {
        super("teleport|tp");
        
        setDescription("Teleport to a player or location");
        setUsage("<player> or <x> <y> <z>");
        setPermission("myplugin.command.teleport");
        setMinArguments(1);
        setCooldown(5, TimeUnit.SECONDS);
        setCooldownBypassPermission("myplugin.cooldown.bypass");
    }
    
    @Override
    protected void onCommand() {
        checkConsole(); // Players only
        
        Player player = getPlayer();
        
        // Teleport to player
        if (args.length == 1) {
            Player target = findPlayer(args[0]);
            
            player.teleport(target.getLocation());
            tellSuccess("Teleported to " + target.getName());
            return;
        }
        
        // Teleport to coordinates
        if (args.length == 3) {
            double x = findNumber(Double.class, 0, "Invalid X coordinate!");
            double y = findNumber(Double.class, 1, "Invalid Y coordinate!");
            double z = findNumber(Double.class, 2, "Invalid Z coordinate!");
            
            Location loc = new Location(player.getWorld(), x, y, z);
            player.teleport(loc);
            
            tellSuccess("Teleported to " + x + ", " + y + ", " + z);
            return;
        }
        
        returnInvalidArgs();
    }
    
    @Override
    protected List<String> tabComplete() {
        if (args.length == 1)
            return completeLastWordPlayerNames();
        
        return NO_COMPLETE;
    }
}