private static Map<String, Parameters> namedParameters() throws GeneralSecurityException {
        Map<String, Parameters> result = new HashMap<>();
        result.put("HMAC_SHA256_PRF", PredefinedPrfParameters.HMAC_SHA256_PRF);
        result.put("HMAC_SHA512_PRF", PredefinedPrfParameters.HMAC_SHA512_PRF);
    return Collections.unmodifiableMap(result);
  }
This key manager generates new {@code HmacPrfKey} keys and produces new instances of {@code
PrfHmacJce}.
java_src/src/main/java/com/google/crypto/tink/prf/HmacPrfKeyManager.java