com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field

You need Setter methods to allow Jackson to set the properties, and you need to change the fields in the json to begin with a lower case letter:

public class Response { private Object ResObj; private int ResInt; public Object getResObj() { return ResObj; } public void setResObj(Object ResObj) { this.ResObj = ResObj; } // ... } 

and:

{"resObj":{"clientNum":"12345","serverNum":"78945","idNum":"020252"},"resInt":0} 

The reason for the JSON change is that the Jackson bean serialisation will reflect over the class, and when it sees getXyz() and setXyz() methods it will map these to a Json field named "xyz" (and not "Xyz").

I think there are several ways to override this behaviour, one is to use the one of the Jackson annotations.

I think you should try this

public class Response { @JsonProperty private Object ResObj; @JsonProperty private int ResInt; public Object getResObj() { return ResObj; } public int getResInt() { return ResInt; } } 

It will resolve your issue with UnrecognizedPropertyExceptions

public class Response { public Object ResObj; public int ResInt; public Object getResObj() { return ResObj; } public int getResInt() { return ResInt; } } 

Use this to resolve the above issue.

I have sorted this problem using the Jackson library. Here is my code snippet.

**Main Class with JSON String in all lower case:** public class MainClass { public static void main(String[] args) throws JsonParseException, JsonMappingException, IOException { String jsonStr = "{\r\n" + " \"resObj\": {\r\n" + " \"clientNum\": \"12345\",\r\n" + " \"serverNum\": \"78945\",\r\n" + " \"idNum\": \"020252\"\r\n" + " },\r\n" + " \"resInt\": 0\r\n" + "}"; ObjectMapper mapper = new ObjectMapper(); MyPojo details = mapper.readValue(jsonStr, MyPojo.class); System.out.println("value of clientNum: " + details.getResObj().getClientNum()); System.out.println("value of getServerNum: " + details.getResObj().getServerNum()); System.out.println("value of getIdNum: " + details.getResObj().getIdNum()); System.out.println("value of getResInt: " + details.getResInt()); } } **MyPojo Class:** public class MyPojo { private ResObj resObj; private String resInt; public ResObj getResObj() { return resObj; } public String getResInt() { return resInt; } } **ResObj class:** public class ResObj { private String serverNum; private String idNum; private String clientNum; public String getServerNum() { return serverNum; } public String getIdNum() { return idNum; } public String getClientNum() { return clientNum; } } **RESULT** value of clientNum: 12345 value of getServerNum: 78945 value of getIdNum: 020252 value of getResInt: 0 NOTE: I have removed Setters in classes & there is no effect on the result. 

I tried all the ways mentioned above but in my case, this is the only solution that worked as answered here Solution 2. Here I have enabled @EnableWebMvc in my spring boot application.

@Configuration @EnableWebMvc public class WebConfig implements WebMvcConfigurer { @Autowired private ObjectMapper objectMapper;// created elsewhere @Override public void extendMessageConverters(List<HttpMessageConverter<?>> converters) { // this will add a 2nd MappingJackson2HttpMessageConverter converters.add(new MappingJackson2HttpMessageConverter(this.objectMapper)); } } 

You need to define another class for the information within ResObj {"ClientNum":"12345","ServerNum":"78945","IdNum":"020252"}. Otherwise jackson cannot determine how to deserialize.