RandomLocation

import java.util.*;
import org.bukkit.Location;
import org.bukkit.Material;
import org.bukkit.World;
import org.bukkit.entity.Player;
import org.bukkit.event.player.PlayerTeleportEvent;

public class RandomLocation
{
    private static class Location2D
    {
        public int highestY(World world)
        {
            Location l = new Location(world, x, 256D, z);
            do
            {
                if(l.getY() <= 0)
                    return 257;
                l.add(0, -1, 0);
            } while(l.getBlock().getType() == Material.AIR);
            return l.getBlockY() + 1;
        }

        public boolean canSpawn(World world)
        {
            Location l = new Location(world, x, 256D, z);
            Material m;
            do
            {
                if(l.getY() <= 0)
                    return false;
                l.add(0, -1, 0);
                m = l.getBlock().getType();
            } while(m == Material.AIR);
            return !l.getBlock().isLiquid() && m != Material.FIRE;
        }

        public void random(Random random, double x0, double z0, double x1, double z1)
        {
            x = random(random, x0, x1);
            z = random(random, z0, z1);
        }
        public static double random(Random random, double min, double max)
        {
            if(min >= max)
                return min;
            else
                return random.nextDouble() * (max - min) + min;
        }

        double x;
        double z;

        Location2D(double x, double z)
        {
            this.x = x;
            this.z = z;
        }
    }
    public void execute(World w, Player p)
    {
        final double x = w.getSpawnLocation().getX();
        final double z = w.getSpawnLocation().getZ();
        final double range = 1000D;

        Location2D loc = new Location2D(x, z);
        Random random = new Random();
        final double x0 = loc.x - range;
        final double z0 = loc.z - range;
        final double x1 = loc.x + range;
        final double z1 = loc.z + range;

        loc.random(random, x0, z0, x1, z1);

        boolean f = true;
        int i;
        for(i = 0; i < 10000 && f; i++)
        {
            f = false;
            if(!loc.canSpawn(w))
            {
                loc.random(random, x0, z0, x1, z1);
                f = true;
            }
        }
        p.teleport(new Location(w, Math.floor(loc.x) + 0.5D, loc.highestY(w), Math.floor(loc.z) + 0.5D), PlayerTeleportEvent.TeleportCause.END_PORTAL);
    }
}