RandomClass.java

public class RandomClass{

  private static final String characters = "abcdefghijklmnopqrstuvwxyz0123456789";

  public static String getRandomString(int length) {
    if (length < 0 || length > 10) {
      return "Random";
    }
    StringBuilder stringBuilder = new StringBuilder();
    Random random = new Random();
    for (int i = 0; i < length; i++) {
      int index = random.nextInt(36);
      stringBuilder.append(characters.charAt(index));
    }
    Utils.putToSleep(1000);
    return stringBuilder.toString();
  }
}