Deserializes a JSON data stream and creates the corresponding Object class.
If gtype implements the Serializable interface, it will be asked to
deserialize all the JSON members into the respective properties; otherwise, the default implementation will be used to translate the
compatible JSON native types.
Note: the JSON data stream must be an object declaration.
| gtype | the Type of object to construct |
| data | a JSON data stream |
| length | length of the data stream, or -1 if it is NUL-terminated |
a Object or null
|