presto-record-decoder/src/main/java/io/prestosql/decoder/json/JsonRowDecoder.java/JsonRowDecoder/locateNode
class JsonRowDecoder:    private static JsonNode locateNode(JsonNode tree, DecoderColumnHandle columnHandle)
    {
        String mapping = columnHandle.getMapping();
        checkState(mapping != null, "No mapping for %s", columnHandle.getName());

        JsonNode currentNode = tree;
        for (String pathElement : Splitter.on('/').omitEmptyStrings().split(mapping)) {
            if (!currentNode.has(pathElement)) {
                return MissingNode.getInstance();
            }
            currentNode = currentNode.path(pathElement);
        }
        return currentNode;
    }