Getting null for inner classes in complex JSON deserialization

Question

I am trying to parse a nested JSON and have generated the apex code using JSON2Apex as below:

global with sharing Class ServiceUpdates 
    {
      @HttpPost
        global static void updateservice()
        { 
            RestRequest r = RestContext.request;
            String jsonRequest = r.requestBody.toString();

                   JSON2Apex wscall = (JSON2Apex)JSON.deserialize(jsonRequest, JSON2Apex.class);
             or    ServiceUpdates.JSON2Apex wscall = (ServiceUpdates.JSON2Apex)JSON.deserialize(jsonRequest, ServiceUpdates.JSON2Apex.class);
             or    ServiceUpdates wscall = (ServiceUpdates)JSON.deserialize(jsonRequest, ServiceUpdates.class); 
            System.debug('response' +wscall );

        }


    public class JSON2Apex 
    {

    public class Services {
            public List<Service> Service;
        }

        public List<Subscriptions> Subscriptions;

        public class Attribute {
            public String name;
            public String value;
        }

        public class Subscriptions {
            public Subscription Subscription;
        }

        public class Service {
            public Attribute attribute;
        }

        public class Subscription {
            public String SAPOrder;
            public String RequestType;
            public String OrderStatus;
            public List<Services> Services;
        }

    }
 }

I'm getting error that Inner types are not allowed to have inner types If I remove the outer-most class from auto generated code and add in existing class then I get NULL in inner object in parsing. Can someone please help how to structure code to parse the json?

UPDATED JSON DETAILS:

{
    "Subscriptions": [
        {
            "Subscription": {
                "SAPOrder": "SAP123",
                "RequestType": "New",
                "OrderStatus": "0",
                "Services": [
                    {
                        "Service": [
                            {
                                "attribute": {
                                    "name": "Resilience",
                                    "value": "Terminated"
                                }
                            },
                            {
                                "attribute": {
                                    "name": "Number",
                                    "value": "1234"
                                }
                            },
                            {
                                "attribute": {
                                    "name": "serviceStartDate",
                                    "value": "2018-08-220T02:13:20"
                                }
                            }
                        ],
                        "Service": [
                            {
                                "attribute": {
                                    "name": "Resilience",
                                    "value": "Terminated"
                                }
                            },
                            {
                                "attribute": {
                                    "name": "Number",
                                    "value": "1234"
                                }
                            },
                            {
                                "attribute": {
                                    "name": "serviceStartDate",
                                    "value": "2018-08-220T02:13:20"
                                }
                            }
                        ]
                    }
                ]
            }
        }
    ]
}

Answer 1

JSON2Apex presumes that the class will be its own top-level class. If you wish to place that class inside another, you also have to move all inner classes from JSON2Apex outside of it. Here's what that looks like:

global with sharing Class ServiceUpdates 
    {
      @HttpPost
        global static void updateservice()
        { 
            RestRequest r = RestContext.request;
            String jsonRequest = r.requestBody.toString();

                   JSON2Apex wscall = (JSON2Apex)JSON.deserialize(jsonRequest, JSON2Apex.class);
             or    ServiceUpdates.JSON2Apex wscall = (ServiceUpdates.JSON2Apex)JSON.deserialize(jsonRequest, ServiceUpdates.JSON2Apex.class);
             or    ServiceUpdates wscall = (ServiceUpdates)JSON.deserialize(jsonRequest, ServiceUpdates.class); 
            System.debug('response' +wscall );

        }

        public class Subscription {
            public String SAPOrder;
            public String RequestType;
            public String OrderStatus;
            public List<Services> Services;
        }
    public class Services {
            public List<Service> Service;
        }
        public class Attribute {
            public String name;
            public String value;
        }

        public class Subscriptions {
            public Subscription Subscription;
        }
        public class Service {
            public Attribute attribute;
        }

    public class JSON2Apex 
    {
        public List<Subscriptions> Subscriptions;
    }
 }

Answer 2

You are getting this error because in its current form, you have 2 level deep of inner class which are not allowed in Apex. Refer to the excerpt from the documentation:

You can only have inner classes one level deep.

In its current form, your class is as:

class ServiceUpdates {
    class JSON2Apex { // level one
        class Services { // level two -- not allowed!
        }
    }
}

You should remove JSON2Apex class from ServiceUpdates and have it as separate class, that should resolve this issue. Something as below:

ServiceUpdates.apxc:

class ServiceUpdates {
}

JSON2Apex.apxc:

class JSON2Apex {
    class Services { // just one level deep now
    }
}