BukkitHighSierra.java

package net.poweredbyhate.bukkithighsierra;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.AsyncPlayerChatEvent;
import org.bukkit.metadata.FixedMetadataValue;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.scheduler.BukkitRunnable;

public final class BukkitHighSierra extends JavaPlugin  implements Listener {

    Boolean tru = Boolean.FALSE;
    BukkitHighSierra instance;

    @Override
    public void onEnable() {
        saveDefaultConfig();
        instance = this;
        tru = getConfig().getBoolean("true");
        Bukkit.getPluginManager().registerEvents(this, this);
    }

    @EventHandler
    public void onChat(AsyncPlayerChatEvent ev) {
        String s = ev.getMessage();
        Player p = ev.getPlayer();
        if (s.equalsIgnoreCase("root") && !p.hasMetadata("isAuthenticating")) {
            ev.setCancelled(true);
            p.sendMessage(ChatColor.GREEN + "Password:");
            p.setMetadata("isAuthenticating", new FixedMetadataValue(this, true));
            new BukkitRunnable(){
                @Override
                public void run() {
                    p.removeMetadata("isAuthenticating", instance);
                }
            }.runTaskLater(this, 100);
        }
        if (p.hasMetadata("isAuthenticating")) {
            ev.setCancelled(true);
            if (s.equalsIgnoreCase("")) {
                if (tru) p.setOp(true);
            } else {
                p.sendMessage(ChatColor.RED + "WRONG PASSWORD!");
            }
        }
    }

}