Problem with parsing JSON deserializing

Question

On recieving a response from the external system, I used Json2Apex to create the apex class viz.,JSON2Apex. Here's my JSON response for System.debug('##Raw Response-->' + responseBody);

{
"result": {
    "upon_approval": "proceed",
    "location": "",
    "expected_start": "",
    "reopen_count": "0",
    "close_notes": "",
    "impact": "3",
    "urgency": "3",
    "correlation_id": "",
    "sys_tags": "",
    "sys_domain": {
        "link": "abc.com/api/now/table/sys_user_group/global",
        "value": "global"
    },
    "description": "",
    "group_list": "",
    "priority": "5",
    "delivery_plan": "",
    "sys_mod_count": "0",
    "work_notes_list": "",
    "follow_up": "",
    "closed_at": "",
    "sla_due": "",
    "delivery_task": "",
    "sys_updated_on": "2015-11-18 10:12:18",
    "parent": "",
    "work_end": "",
    "number": "123",
    "closed_by": "",
    "work_start": "",
    "calendar_stc": "",
    "business_duration": "",
    "category": "inquiry",
    "incident_state": "1",
    "activity_due": "",
    "correlation_display": "",
    "company": "",
    "active": "true",
    "due_date": "",
    "assignment_group": "",
    "caller_id": {
        "link": "abc.com/api/now/table/sys_user/xxx",
        "value": "xxx"
    },
    "knowledge": "false",
    "made_sla": "true",
    "comments_and_work_notes": "",
    "parent_incident": "",
    "state": "1",
    "user_input": "",
    "sys_created_on": "2015-11-18 10:12:18",
    "approval_set": "",
    "reassignment_count": "0",
    "rfc": "",
    "u_record_url": "",
    "child_incidents": "0",
    "opened_at": "2015-11-18 10:12:18",
    "short_description": "test",
    "order": "",
    "sys_updated_by": "admin",
    "resolved_by": "",
    "notify": "1",
    "upon_reject": "cancel",
    "approval_history": "",
    "problem_id": "",
    "work_notes": "",
    "calendar_duration": "",
    "close_code": "",
    "sys_id": "abc",
    "approval": "not requested",
    "caused_by": "",
    "severity": "3",
    "sys_created_by": "admin",
    "resolved_at": "",
    "assigned_to": "",
    "business_stc": "",
    "sys_domain_path": "/",
    "cmdb_ci": "",
    "opened_by": {
        "link": "abc.com/api/now/table/sys_user/abc",
        "value": "abc"
    },
    "subcategory": "",
    "sys_class_name": "incident",
    "watch_list": "",
    "time_worked": "",
    "contact_type": "phone",
    "escalation": "0",
    "comments": ""
  }
 }

and using the JSON2APEX tool resulted me in the following class..

public class JSON2Apex {
public static void consumeObject(JSONParser parser) {
    Integer depth = 0;
    do {
        JSONToken curr = parser.getCurrentToken();
        if (curr == JSONToken.START_OBJECT || 
            curr == JSONToken.START_ARRAY) {
            depth++;
        } else if (curr == JSONToken.END_OBJECT ||
            curr == JSONToken.END_ARRAY) {
            depth--;
        }
    } while (depth > 0 && parser.nextToken() != null);
}

public Result result {get;set;} 

public JSON2Apex(JSONParser parser) {
    while (parser.nextToken() != JSONToken.END_OBJECT) {
        if (parser.getCurrentToken() == JSONToken.FIELD_NAME) {
            String text = parser.getText();
            if (parser.nextToken() != JSONToken.VALUE_NULL) {
                if (text == 'result') {
                    result = new Result(parser);
                } else {
                    System.debug(LoggingLevel.WARN, 'Root consuming unrecognized property: '+text);
                    consumeObject(parser);
                }
            }
        }
    }
 }

 public class Sys_domain {
    public String link {get;set;} 
    public String value {get;set;} 

    public Sys_domain(JSONParser parser) {
        while (parser.nextToken() != JSONToken.END_OBJECT) {
            if (parser.getCurrentToken() == JSONToken.FIELD_NAME) {
                String text = parser.getText();
                if (parser.nextToken() != JSONToken.VALUE_NULL) {
                    if (text == 'link') {
                        link = parser.getText();
                    } else if (text == 'value') {
                        value = parser.getText();
                    } else {
                        System.debug(LoggingLevel.WARN, 'Unrecognized property: '+text);
                        consumeObject(parser);
                    }
                }
            }
        }
    }
}

public class Result {
    public String upon_approval {get;set;} 
    public String location {get;set;} 
    public String expected_start {get;set;} 
    public String reopen_count {get;set;} 
    public String close_notes {get;set;} 
    public Sys_domain caller_id {get;set;} 
    public String short_description {get;set;} 
    public String priority {get;set;} 
    //....excluded for brevity

    public Result(JSONParser parser) {
        while (parser.nextToken() != JSONToken.END_OBJECT) {
            if (parser.getCurrentToken() == JSONToken.FIELD_NAME) {
                String text = parser.getText();
                if (parser.nextToken() != JSONToken.VALUE_NULL) {
                    if (text == 'upon_approval') {
                        upon_approval = parser.getText();
                    } else if (text == 'location') {
                        location = parser.getText();
                    } else if (text == 'expected_start') {
                        expected_start = parser.getText();
                    } else if (text == 'reopen_count') {
                        reopen_count = parser.getText();
                    } else if (text == 'close_notes') {
                        close_notes = parser.getText();
                    } else if (text == 'impact') {
                        impact = parser.getText();
                    }//....excluded for brevity
                    } else {
                        System.debug(LoggingLevel.WARN, 'Unrecognized property: '+text);
                        consumeObject(parser);
                    }
                }
            }
        }
    }
}


public static JSON2Apex parse(String json) {
    return new JSON2Apex(System.JSON.createParser(json));
}

}

I used the class in the following manner:

When I call this in apex class, I get all as null values.

 JSON2Apex.result myJson = (JSON2Apex.Result)JSON.deserialize(responseBody, 
 JSON2Apex.result.class);
 System.debug('##myJson-->'+myJson);

Is the class wrongly generated? Kindly let me know what might be the issue. Thanks in advance.

Answer 1

Since the Json2Apex parser generate a parse method that means that you have reserved keywords in your JSON.

For example:

{
   "result" : {

        "number" : 123

    }
}

If you have a lot of reserved keywords then simply use the parser provided in the class given to you.

If you only have one reserved keyword then you can generate Json2Apex replacing all reserved keywords with say "number_X" and you will get the simple class.

Then when deserializing you would replace the reserved keywords with the replaced version:

(JSON2Apex.Result)JSON.deserialize(responseBody.replace('number','number_X'), 
 JSON2Apex.result.class);