src/main/java/com/conveyal/gtfs/loader/JdbcTableWriter.java
private static JsonNode getJsonNode (String json) throws IOException {
        try {
            return mapper.readTree(json);
        } catch (IOException e) {
            LOG.error("Bad JSON syntax", e);
            throw e;
        }
    }
private static JsonNode getJsonNode (String json) throws IOException {
        try {
            return mapper.readTree(json);
        } catch (IOException e) {
            LOG.error("Bad JSON syntax", e);
            throw e;
        }
    }
Wrapper method to call Jackson to deserialize a JSON string into JsonNode.