ByteUtil { public static String toHexString(byte[] data) { return data == null ? "" : Hex.toHexString(data); }  static byte[] appendByte(byte[] bytes, byte b); static byte[] bigIntegerToBytes(BigInteger b, int numBytes); static byte[] bigIntegerToBytes(BigInteger value); static int matchingNibbleLength(byte[] a, byte[] b); static byte[] longToBytes(long val); static String toHexString(byte[] data); static byte[] calcPacketLength(byte[] msg); static int byteArrayToInt(byte[] b); static String nibblesToPrettyString(byte[] nibbles); static String oneByteToHexString(byte value); static int numBytes(String val); static byte[] encodeValFor32Bits(Object arg); static byte[] encodeDataList(Object... args); static byte[] stripLeadingZeroes(byte[] data); static boolean increment(byte[] bytes); static byte[] copyToArray(BigInteger value); static final byte[] EMPTY_BYTE_ARRAY; }
@Test public void testToHexString() { assertEquals("", ByteUtil.toHexString(null)); }