System.out.println(row) will call toString() on row... which will call toString() on each map entry which will call toString() on each object value. The value you're seeing is the default Java Date.toString(). Can you inspect the individual objects and confirm that the API is giving you Date objects? If so, the API is doing what its supposed to do... translating each JSON value into the appropriate Java object. If you want to display Dates in a specific format your code will need to implement this via DateFormat or similar.

Adam