public class PotionEffectz implements CommandExecutor {

    @Override
    public boolean onCommand(CommandSender commandSender, Command command, String s, String[] strings) {

        if(s.equalsIgnoreCase("potioneffectz")) {
            if(!(commandSender instanceof Player)) {
                commandSender.sendMessage(ChatColor.RED + "You must be a player");
                return true;

            }
            Player p = (Player) commandSender;

            if(!p.hasPermission("pve.command")) {
                p.sendMessage(ChatColor.RED + "No permissions");
                return true;

            }

            if(strings.length != 1) {
                p.sendMessage(ChatColor.RED + "Usage: /potioneffectz <effect>");
                return true;
            }
            String type = strings[0];

            if(type == "speed") {
                p.addPotionEffect(new PotionEffect(PotionEffectType.SPEED, 200, 1));
                p.sendMessage(ChatColor.YELLOW + "Successfully given you speed!");
                return true;
            }

            if(type == "absorb") {
                p.addPotionEffect(new PotionEffect(PotionEffectType.ABSORPTION, 200, 1));
                p.sendMessage(ChatColor.YELLOW + "Successfully given you Absorption!");
                return true;
            }

        }

        return true;
    }
}