My First Plugin

package me.nathan.myfirstplugin;

import me.nathan.myfirstplugin.commands.PluginCommands;
import me.nathan.myfirstplugin.events.PluginEvents;
import org.bukkit.ChatColor;
import org.bukkit.plugin.java.JavaPlugin;

public final class MyFirstPlugin extends JavaPlugin {

    @Override
    public void onEnable() {
        getServer().getPluginManager().registerEvents(new PluginEvents(), this);
        getCommand("heal").setExecutor(new PluginCommands(this));
        getServer().getConsoleSender().sendMessage(ChatColor.AQUA + "[MyFirstPlugin]: Plugin is enabled!");
    }

    @Override
    public void onDisable() {
        // Plugin shutdown logic
        getServer().getConsoleSender().sendMessage(ChatColor.RED + "[MyFirstPlugin]: Plugin is disabled!");
    }
}

package me.nathan.myfirstplugin.commands;

import me.nathan.myfirstplugin.MyFirstPlugin;
import org.bukkit.ChatColor;
import org.bukkit.attribute.Attribute;
import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;

import java.util.Objects;

public class PluginCommands implements CommandExecutor {
    private final MyFirstPlugin main;

    public PluginCommands(MyFirstPlugin main){
        this.main = main;
    }

    @Override
    public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {
        if (sender instanceof Player){
            Player player = (Player) sender;
            if (player.isOp() || player.hasPermission("canHeal")){
                double maxHealth = Objects.requireNonNull(player.getAttribute(Attribute.GENERIC_MAX_HEALTH)).getDefaultValue();
                player.setHealth(maxHealth);
                player.sendMessage("§e§l(!) §eYou have been healed!");
                return true;
            } else {
                player.sendMessage(ChatColor.RED + "You do not have the required permissions to use this command!");
                return true;
            }

        } else {
            main.getLogger().info(ChatColor.RED + "You have to be a player to use that command!");
            return true;
        }
    }
}

name: FirstPlugin
author: N8TheDev
description: First Plugin
version:  1.0
api-version: 1.17.1
main: me.nathan.myfirstplugin.MyFirstPlugin
commands:
  heal:
    description: Heals you
    usage: /<command>