@Test
    public void shouldConvertTimestampValues() {
        java.util.Date current = new java.util.Date();
        long currentMillis = current.getTime() % MILLIS_PER_DAY;

        // java.util.Date - just copy
        java.util.Date ts1 = Values.convertToTimestamp(Timestamp.SCHEMA, current);
        assertEquals(current, ts1);

        // java.util.Date as a Timestamp - discard the day's milliseconds and keep the date
        java.util.Date currentDate = new java.util.Date(current.getTime() - currentMillis);
        ts1 = Values.convertToTimestamp(Date.SCHEMA, currentDate);
        assertEquals(currentDate, ts1);

        // java.util.Date as a Time - discard the date and keep the day's milliseconds
        ts1 = Values.convertToTimestamp(Time.SCHEMA, currentMillis);
        assertEquals(new java.util.Date(currentMillis), ts1);

        // ISO8601 strings - currently broken because tokenization breaks at colon

        // Millis as string
        java.util.Date ts3 = Values.convertToTimestamp(Timestamp.SCHEMA, Long.toString(current.getTime()));
        assertEquals(current, ts3);

        // Millis as long
        java.util.Date ts4 = Values.convertToTimestamp(Timestamp.SCHEMA, current.getTime());
        assertEquals(current, ts4);
    }
This is technically invalid JSON, and we don't want to simply ignore the blank entry.
connect/api/src/test/java/org/apache/kafka/connect/data/ValuesTest.java