My code is very simple (using commons-codec-1.10.jar)
Hex.encodeHex is working fine, but the results are the UTF-8 encoding, whereas codebeautify.org appears to be using UTF-16.
Let's take 三 to start with. That's U+4E09. In UTF-16 that's encoded as 4E 09, which matches the start of your codebeautify output. In UTF-8 it's encoded as E4 B8 89, which matches your Java output.
If you want UTF-16, just use
StandardCharsets.UTF_16BE instead of
StandardCharsets.UTF_8. (But only do it if you really want UTF-16. UTF-8 is a better encoding to use in most cases, IMO.)