CharUtils { public static boolean isAlphaNumeric(char a) { return isAlpha(a) || isNumeric(a); } 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 testCharUtilsIsAlphaNumeric() { char[] arr = { 'a', 'G', '3', '9' }; for (char a : arr) { Assert.assertTrue(CharUtils.isAlphaNumeric(a)); } char[] arr2 = { '~', '-', '_', '\n' }; for (char a : arr2) { Assert.assertFalse(CharUtils.isAlphaNumeric(a)); } }