### Question:
NumericUtil { public static byte[] hexToBytes(String input) { String cleanInput = cleanHexPrefix(input); int len = cleanInput.length(); if (len == 0) { return new byte[]{}; } byte[] data; int startIdx; if (len % 2 != 0) { data = new byte[(len / 2) + 1]; data[0] = (byte) Character.digit(cleanInput.charAt(0), 16); startIdx = 1; } else { data = new byte[len / 2]; startIdx = 0; } for (int i = startIdx; i < len; i += 2) { data[(i + 1) / 2] = (byte) ((Character.digit(cleanInput.charAt(i), 16) << 4) + Character.digit(cleanInput.charAt(i + 1), 16)); } return data; }  static byte[] generateRandomBytes(int size); static boolean isValidHex(String value); static String cleanHexPrefix(String input); static String prependHexPrefix(String input); static BigInteger bytesToBigInteger(byte[] value, int offset, int length); static BigInteger bytesToBigInteger(byte[] value); static BigInteger hexToBigInteger(String hexValue); static String bigIntegerToHex(BigInteger value); static String bigIntegerToHexWithZeroPadded(BigInteger value, int size); static byte[] bigIntegerToBytesWithZeroPadded(BigInteger value, int length); static byte[] hexToBytes(String input); static byte[] hexToBytesLittleEndian(String input); static byte[] reverseBytes(byte[] bytes); static String bytesToHex(byte[] input); static String beBigEndianHex(String hex); static String beLittleEndianHex(String hex); static int bytesToInt(byte[] bytes); static byte[] intToBytes(int intValue);  }### Answer:
@Test public void testHexToBytes() { Object[][] example = new Object[][] { new Object[] { new byte[]{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, "0x1010101010101010101010101010101010101010101010101010101010101010101010101010101" }, new Object[] { new byte[]{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, "1010101010101010101010101010101010101010101010101010101010101010101010101010101" }, new Object[] { new byte[] { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }, "0x010101010101010101010101" }, new Object[] { new byte[] { 1,1,1 }, "0x10101" }, new Object[] { new byte[0], "" }, }; for(Object[] test : example) { assertArrayEquals((byte[])test[0], NumericUtil.hexToBytes((String)test[1])); } }