CharUtils { public static boolean isAlpha(char a) { return ((a >= 'a' && a <= 'z') || (a >= 'A' && a <= 'Z')); } private  CharUtils(); static boolean isHex(char a); static boolean isAlpha(char a); static boolean isNumeric(char a); static boolean isAlphaNumeric(char a); static boolean isUnreserved(char a); static boolean isDot(char a); static boolean isWhiteSpace(char a); static String[] splitByDot(String input);  }
@Test public void testCharUtilsIsAlpha() { char[] arr = { 'a', 'Z', 'f', 'X' }; for (char a : arr) { Assert.assertTrue(CharUtils.isAlpha(a)); } char[] arr2 = { '0', '9', '[', '~' }; for (char a : arr2) { Assert.assertFalse(CharUtils.isAlpha(a)); } }