private static Optional<JsonNode> getValue(final ObjectNode node, final String key) {
    final JsonNode jsonNode = node.get(key);
    if (jsonNode == null || jsonNode.isNull()) {
      return Optional.empty();
    }
    return Optional.of(jsonNode);
  }
Gets array node.

@param json the json
@param fieldKey the field key
@param strict true for strict mode
@return the array node
config/src/main/java/org/hyperledger/besu/config/JsonUtil.java