### Question:
StringUtils { public static boolean isNumeric(char[] str) { for (char c : str) { if (!Character.isDigit(c)) { return false; } } return true; }  static boolean isCharEqual(char[] str); static boolean isNumeric(char[] str); static boolean isContains(char[] a, char[] b); static void clear(char[] a); static void clear(byte[] a); static byte[] char2Byte(char[] a); static char[] byte2Char(byte[] a); static void printOneByte(byte b); static byte[] hexs2Bytes(byte[] a);  }### Answer:
@Test public void isNumeric() { char[] a = "0123456".toCharArray(); char[] b = "123456a".toCharArray(); Assert.assertTrue(StringUtils.isNumeric(a)); Assert.assertFalse(StringUtils.isNumeric(b)); }