private JsonNode parse(String json) {
        try {
            return objectMapper.readTree(json);
        } catch (IOException e) {
            fail("IOException during JSON parse: " + e.getMessage());
            throw new RuntimeException("failed");
        }
    }
When schemas are disabled, fields are mapped to Connect maps.
connect/json/src/test/java/org/apache/kafka/connect/json/JsonConverterTest.java