Null properties are dropped during marshalling/unmarshalling with JSONIX

I noticed that in my conversion from JSON to XML, if one of my JSON objects is null, the node for that property is absent from the XML, for example

JSON

```
{
"name": {
"namespaceURI": "",
"localPart": "myApp",
"prefix": "",
"key": "myApp",
"string": "myApp"
},
"value": {
"TYPE_NAME": "generated.MyApp",
"inputData": [{
"TYPE_NAME": "generated.MyApp.InputData",
"dataType": "text",
"mandatory": false,
"length": 25,
"valid": true,
"value":null
}]
}
}
```

Convert to XML output (marshalString)

```
var context2 = new j.Context([generated2]);
var marshaller2 = context2.createMarshaller();
var objectAsXMLString2 = marshaller2.marshalString(template2);
```

```

text
false
25
true

```

Then converting back again to JSON (unmarshalString)

```
var unmarshaller2 = context2.createUnmarshaller();
var resultJSON2 = unmarshaller2.unmarshalString(objectAsXMLString2 );
```

```
{
"name": {
"namespaceURI": "",
"localPart": "myApp",
"prefix": "",
"key": "myApp",
"string": "myApp"
},
"value": {
"TYPE_NAME": "generated.MyApp",
"inputData": [{
"TYPE_NAME": "generated.MyApp.InputData",
"dataType": "text",
"mandatory": false,
"length": 25,
"valid": true
}]
}
}
```

So as you see, there is loss of information. When the complete cycle of conversion occurs, JSON -> XML -> back to JSON, some properties are not preserved. Anything that is null gets dropped - in this case it is the property 'value'. This is a problem for downstream applications that are expecting certain properties to be present on an object.

My XML schema that was used to generate the jsonix mapping object looks like this

```

```

And generated mapping using jsonix-schema-compiler is

```
var generated_Module_Factory = function () {
var generated = {
name: 'generated',
typeInfos: [{
localName: 'MyApp',
typeName: null,
propertyInfos: [{
name: 'inputData',
minOccurs: 0,
collection: true,
elementName: {
localPart: 'inputData'
},
typeInfo: '.MyApp.InputData'
}]
}, {
localName: 'MyApp.InputData',
typeName: null,
propertyInfos: [{
name: 'dataType',
required: true,
elementName: {
localPart: 'dataType'
}
}, {
name: 'mandatory',
required: true,
elementName: {
localPart: 'mandatory'
},
typeInfo: 'Boolean'
}, {
name: 'length',
required: true,
elementName: {
localPart: 'length'
},
typeInfo: 'Short'
}, {
name: 'elementId',
required: true,
elementName: {
localPart: 'elementId'
}
}, {
name: 'formId',
required: true,
elementName: {
localPart: 'formId'
}
}, {
name: 'value',
required: true,
elementName: {
localPart: 'value'
},
typeInfo: 'AnySimpleType'
}, {
name: 'valid',
required: true,
elementName: {
localPart: 'valid'
},
typeInfo: 'Boolean'
}, {
name: 'precision',
required: true,
elementName: {
localPart: 'precision'
},
typeInfo: 'Short'
}, {
name: 'scale',
required: true,
elementName: {
localPart: 'scale'
},
typeInfo: 'Short'
}]
}],
elementInfos: [{
typeInfo: '.MyApp',
elementName: {
localPart: 'myApp'
}
}]
};
return {
generated: generated
};
};
if (typeof define === 'function' && define.amd) {
define([], generated_Module_Factory);
}
else {
var generated_Module = generated_Module_Factory();
if (typeof module !== 'undefined' && module.exports) {
module.exports.generated = generated_Module.generated;
}
else {
var generated = generated_Module.generated;
}
}
```

Is there a way to preserve all properties during the conversion, even if they are null?