Answer by Muxammed Gafarov for How to generate a random alpha-numeric string

public class Utils {    private final Random RANDOM = new SecureRandom();    private final String ALPHABET = "0123456789QWERTYUIOPASDFGHJKLZXCVBNMqwertyuiopasdfghjklzxcvbnm";    private String generateRandomString(int length) {        StringBuffer buffer = new StringBuffer(length);        for (int i = 0; i < length; i++) {            buffer.append(ALPHABET.charAt(RANDOM.nextInt(ALPHABET.length())));        }        return new String(buffer);    } }