Java JSON backslash added to JSON response

Question

Why these backslash is coming and how to remove them while browser displays the json data to the client?

The o/p json response seems to be valid if those backslash(es) were not present

testbookdata.xml

<Users>
    <User>
        <Name>Unni</Name>
        <Books>
            <Book>book1</Book>
            <Book>book2</Book>
            <Book>book3</Book>
        </Books>
    </User>
    <User>
        <Name>Ammu</Name>
        <Books>
            <Book>book1</Book>
            <Book>book2</Book>
            <Book>book4</Book>
        </Books>
    </User>
</Users>

This xml is converted to a JSONObject thru org.json library

org.json.JSONObject xmlJSONObj = XML.toJSONObject(booksXMLString);

Finally I have a class that tells what all to be converted to JSON on a particular user request,

A property of the class:

@JsonInclude(Include.NON_NULL)
@JsonProperty(value = "jsondata")
public String getJson() {
    return json.toString();
}

If I just print the data,

json data : ...
{"Users":{"User":[{"Name":"Unni","Books":{"Book":["book1","book2","book3"]}},{"Name":"Ammu","Books":{"Book":["book1","book2","book4"]}}]}}

Finally the webservice controller method which has a public @ResponseBody annotation calls the service and returns the object that has the @Json annotations

Problem:

When the result is displayed by the browser, it is like this -

"jsondata": "{\"Users\":{\"User\":[{\"Name\":\"Unni\",\"Books\":{\"Book\":[\"book1\",\"book2\",\"book3\"]}},{\"Name\":\"Ammu\",\"Books\":{\"Book\":[\"book1\",\"book2\",\"book4\"]}}]}}"
}

How to overcome this issue?

Thanks!

note: I added spring-mvc tag because @ResponseBody is part of spring-web

Update 1:

Tried again what @Jon Skeet has mentioned, however that gives the error,

org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: 
No serializer found for class org.json.JSONObject and no properties discovered to create 
BeanSerializer (to avoid exception, disable SerializationConfig.SerializationFeature.FAIL_ON_EMPTY_BEANS) ) 
(through reference chain: com.ht.Result["jsondata"]);
 nested exception is com.fasterxml.jackson.databind.JsonMappingException: 
 No serializer found for class org.json.JSONObject and no properties discovered 
 to create BeanSerializer (to avoid exception, disable SerializationConfig.SerializationFeature
 .FAIL_ON_EMPTY_BEANS) )

Answer 1

From what I understand, you have

class SomePojo {
    public JSONObject json;
    @JsonInclude(Include.NON_NULL)
    @JsonProperty(value = "jsondata")
    public String getJson() {
        return json.toString();
    }
}

and

@ResponseBody
@RequestMapping(..)
public SomePojo getPojo() {
    SomePojo pojo = ...;
    return pojo;
}

The model above is basically saying that you have a JSON object which contains a name-value pair. The name is jsondata and the value is a JSON String. Since your String value contains characters that are not acceptable in a JSON String, they must be escaped in the serialized value.

But you seem to want a JSON object which contains a name-value pair where the name is jsondata and the value is another JSON object.

You probably want to have

@JsonRawValue
@JsonInclude(Include.NON_NULL)
@JsonProperty(value = "jsondata")
public String getJson() {
    return json.toString();
}

So that the String value is used as is, rather than converted to a JSON String.