RandUtil { public static String nextAlphabetic(int characters) { StringBuffer buffer = new StringBuffer(); for (int i = 0; i < characters; i++) { if (nextBoolean()) buffer.append((char) nextInt('A', 'Z')); else buffer.append((char) nextInt('a', 'z')); } return buffer.toString(); } private  RandUtil(); static boolean nextBoolean(); static int nextInt(); static int nextInt(int lower, int upper); static long nextLong(long n); static long nextLong(long lower, long upper); static long nextLong(); static String nextAlphabetic(int characters); static String nextNumeric(int digits); static E nextItem(E[] array);  }
@Test @DisplayName("Test alphabetic string generation") void nextAlphabetic_1() { assertEquals("", RandUtil.nextAlphabetic(0)); for (char c : RandUtil.nextAlphabetic(1000).toCharArray()) { assertTrue(Character.isLetter(c)); } }