### Question:
Numeric { public static String toHexString(byte[] input, int offset, int length, boolean withPrefix) { StringBuilder stringBuilder = new StringBuilder(); if (withPrefix) { stringBuilder.append("0x"); } for (int i = offset; i < offset + length; i++) { stringBuilder.append(String.format("%02x", input[i] & 0xFF)); } return stringBuilder.toString(); } private  Numeric(); static String encodeQuantity(BigInteger value); static BigInteger decodeQuantity(String value); static String cleanHexPrefix(String input); static String prependHexPrefix(String input); static boolean containsHexPrefix(String input); static BigInteger toBigInt(byte[] value, int offset, int length); static BigInteger toBigInt(byte[] value); static BigInteger toBigInt(String hexValue); static BigInteger toBigIntNoPrefix(String hexValue); static String toHexStringWithPrefix(BigInteger value); static String toHexStringNoPrefix(BigInteger value); static String toHexStringNoPrefix(byte[] input); static String toHexStringWithPrefixZeroPadded(BigInteger value, int size); static String toHexStringNoPrefixZeroPadded(BigInteger value, int size); static byte[] toBytesPadded(BigInteger value, int length); static byte[] hexStringToByteArray(String input); static String toHexString(byte[] input, int offset, int length, boolean withPrefix); static String toHexString(byte[] input); static byte asByte(int m, int n); static boolean isIntegerValue(BigDecimal value);  }### Answer:
@Test public void testToHexString() { assertThat(Numeric.toHexString(new byte[] {}), is("0x")); assertThat(Numeric.toHexString(new byte[] { 0x1 }), is("0x01")); assertThat(Numeric.toHexString(HEX_RANGE_ARRAY), is(HEX_RANGE_STRING)); }