Deserialize JSON into existing object (Java)

Question

I'd like to know how one might get the Jackson JSON library to deserialize JSON into an existing object? I've tried to find how to to this; but it seems to only be able to take a Class and instantiate it itself.

Or if not possible, I'd like to know if any Java JSON deserialization libraries can do it.

This seems to be a corresponding question for C#: Overlay data from JSON string to existing object instance. It seems JSON.NET has a PopulateObject(string,object).

Answer 1

You can do this using Jackson:

mapper.readerForUpdating(object).readValue(json);

See also Merging Two JSON Documents Using Jackson