@Test
    public void dateToConnect() {
        Schema schema = Date.SCHEMA;
        GregorianCalendar calendar = new GregorianCalendar(1970, Calendar.JANUARY, 1, 0, 0, 0);
        calendar.setTimeZone(TimeZone.getTimeZone("UTC"));
        calendar.add(Calendar.DATE, 10000);
        java.util.Date reference = calendar.getTime();
        String msg = "{ \"schema\": { \"type\": \"int32\", \"name\": \"org.apache.kafka.connect.data.Date\", \"version\": 1 }, \"payload\": 10000 }";
        SchemaAndValue schemaAndValue = converter.toConnectData(TOPIC, msg.getBytes());
        java.util.Date converted = (java.util.Date) schemaAndValue.value();
        assertEquals(schema, schemaAndValue.schema());
        assertEquals(reference, converted);
    }
When schemas are disabled, fields are mapped to Connect maps.
connect/json/src/test/java/org/apache/kafka/connect/json/JsonConverterTest.java