Question

I’ve got a class written in Java and the same class written in C#. I’m serializing the C# class into a json string and I am trying to deserialize it on the Java side.
It all went perfectly fine until I’ve added a byte[] field to both classes.
here are the classes definitions:
C#:

public class RegisterRequest : GenericRequest
{
    public string name { set; get; }
    public string sex { set; get; }
    public string birthday { set; get; }
    public string from { set; get; }
    public string about { set; get; }
    public byte[] image { set; get; }
}

Java:

public class RegisterRequest extends GenericRequest{
    private String name;
    private String sex;
    private String birthday;
    private String from;
    private String about;
    private String pictureUrl;
    private byte[] image;
}

The serialization on the C# side uses: request.ToJson() (Json.NET)
and the Java deserialization uses: RegisterRequest rr = gsonObject.fromJson(msg, RegisterRequest.class); (using Gson. the msg is the json string)

When I don’t send anything in the byte array it still works. But when I do fill the array I get an exception on the Java side: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 159089

I’m guessing that there needs to be something that marks the begining of an array which Gson identifies but Json.NET doesn’t adds to the string?

Answer 1

Given the piece of input from a comment above

"image":"/9j/4AAQSkZJRgAB..."

and looking at how Gson serializes byte[]

"a":[96,-76,32,-69,56,81,-39,-44...

the answer is obvious: Gson uses a json array while json.net uses a json string. You must change one or the other. Writing a custom serializer for gson is easy (although I’ve never tried with byte[]), the same probably holds for the other tool.