How to serialize Optional classes with Gson?

Question

I have an object with the following attributes.

private final String messageBundle;
private final List messageParams;
private final String acti         


        

Answer 1

I'll add to Anton Onikiychuk's answer

@Override
public Optional read(JsonReader in) throws IOException {
    JsonToken peek = in.peek();
    if (peek == JsonToken.NULL) {
        in.nextNull(); // consuming JSON null
        return Optional.empty();
    }

    return Optional.ofNullable(adapter.read(in));
}