PrintScreen Randomizer

import java.util.Random;
public class UrlRandomizer{
        Random rng = new Random();
        private int num1 = 0;
        private int num2 = 0;
        private int num3 = 0;
        private int num4 = 0;
        private int num5 = 0;
        private int num6 = 0;
        String url = "prntscr.com/";
        String [] chars = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "a", "b", "c", "d", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "x", "y", "z"};
        public String randomURL(){
                num1 = rng.nextInt(chars.length-1);
                num2 = rng.nextInt(chars.length-1);
                num3 = rng.nextInt(chars.length-1);
                num4 = rng.nextInt(chars.length-1);
                num5 = rng.nextInt(chars.length-1);
                num6 = rng.nextInt(chars.length-1);
                System.out.println(url + chars[num1] + chars[num2] + chars[num3] + chars[num4] + chars[num5] + chars[num6]);
                return url + chars[num1] + chars[num2] + chars[num3] + chars[num4] + chars[num5] + chars[num6];
        }
}