@Override
  public long newNonce() {
    long result = HConstants.NO_NONCE;
    do {
      result = ThreadLocalRandom.current().nextLong();
    } while (result == HConstants.NO_NONCE);
    return result;
  }
NonceGenerator implementation that uses client ID hash + random int as nonce group, and random
numbers as nonces.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/PerClientRandomNonceGenerator.java