### Question:
HDUtils { static byte[] longTo4ByteArray(long n) { byte[] bytes = Arrays.copyOfRange(ByteBuffer.allocate(8).putLong(n).array(), 4, 8); assert bytes.length == 4 : bytes.length; return bytes; }  static byte[] hmacSha512(byte[] key, byte[] data); @Deprecated static HDPath append(List<ChildNumber> path, ChildNumber childNumber); @Deprecated static HDPath concat(List<ChildNumber> path, List<ChildNumber> path2); @Deprecated static String formatPath(List<ChildNumber> path); @Deprecated static HDPath parsePath(@Nonnull String path);  }### Answer:
@Test public void testLongToByteArray() throws Exception { byte[] bytes = HDUtils.longTo4ByteArray(1026); Assert.assertEquals("00000402", HEX.encode(bytes)); }