Randoms { public static String alphaNumeric(int length) { StringBuilder builder = new StringBuilder(length); for (int i = 0; i < length; i++) builder.append(ALPHA_NUMERIC.charAt(ThreadLocalRandom.current().nextInt(ALPHA_NUMERIC.length()))); return builder.toString(); }  static String alphaNumeric(int length); static double number(double min, double max);  }
@Test void randomAlphaNumeric() { assertThat(Randoms.alphaNumeric(3)).hasSize(3); assertThat(Randoms.alphaNumeric(5)).hasSize(5); assertThat(Randoms.alphaNumeric(10)).hasSize(10); }