SecureRandom

import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
 
public class Helper {
 
    public static void main(String[] args) throws NoSuchAlgorithmException {
        String [] strBox = {"111", "222", "333", "444"};
        SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
        for (int i = 0; i < 11; i++) {
            System.out.println(strBox[random.nextInt(strBox.length)]);
        }
    }
}

String[] words = {"a", "b", "c"};
String password = words[(int) (Math.random() * words.length)];
byte[] keys = key.getBytes();