랜덤 텔레포트 플러그인을 만들고있는데

자꾸 땅속에서 스폰되는 경우가 생기네요

코드는 다음과 같습니다:

public class TeleportUtils {

    public static Location generateLocation(Player player){
        Random random = new Random();
        World over = Bukkit.getServer().getWorld("world_overworld");


        int x = random.nextInt(5000)*(random.nextBoolean() ?-1:+1);
        int y = 150;
        int z = random.nextInt(5000)*(random.nextBoolean() ?-1:+1);

        Location randomLocation = new Location(over, x, y, z);

        y = randomLocation.getWorld().getHighestBlockYAt(randomLocation);
        randomLocation.setY(y);

        return randomLocation;
    }
}