getRandomInt getRandomString

import java.util.concurrent.ThreadLocalRandom;

private static final String AB = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

  public int getRandomInt() {
    return ThreadLocalRandom.current().nextInt(10000, 100000);
  }

  public String getRandomString(int length) {
    StringBuilder sb = new StringBuilder(length);
    for (int i = 0; i < length; i++) {
      sb.append(AB.charAt(ThreadLocalRandom.current().nextInt(AB.length())));
    }
    return sb.toString();
  }