hkdf

In the application I'm writing I need to do HKDF to derive two different keys from one password. Searching for examples on how to it in Java I found these two: https://github.com/WhisperSystems/libsignal-protocol-java/blob/master/java/src/main/java/org/whispersystems/libsignal/kdf/HKDF.java https://www.javatips.net/api/keywhiz-master/hkdf/src/main/java/keywhiz/hkdf/Hkdf.java In both cases HKDF is implemented on top of the HMAC provided by JCA. I haven't read those implementations in detail yet but I was wondering, is this not implemented anywhere in JCA or itself? Do I have to implement my own