Create a Nested JSON Object using ObjectMapper

To create a nested JSON Object or put another JSON Object as field value, we can not use put(String fieldName, JsonNode fieldValue) as it is deprecated. We use set(String fieldName, JsonNode fieldValue) or replace(String fieldName, JsonNode fieldValue)

// Create an object to ObjectMapper
ObjectMapper objectMapper = new ObjectMapper();
		
// Creating Node that maps to JSON Object structures in JSON content
ObjectNode employeeInfo = objectMapper.createObjectNode();
ObjectNode employeeDetails = objectMapper.createObjectNode();

employeeDetails.put("firstname", "Phani");
employeeDetails.put("lastname", "Nagula");

employeeInfo.set("employee", "employeeDetails");

// To print created json object
String createdPlainJsonObject = objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(employeeInfo);
System.out.println("Created plain JSON Object is : \n"+ createdPlainJsonObject);