How do I add a type to GWT's Serialization Policy whitelist?

Question

GWT\'s serializer has limited java.io.Serializable support, but for security reasons there is a whitelist of types it supports. The documentation I\'ve found,

Answer 1

There's a workaround: define a new Dummy class with member fields of all the types that you want to be included in serialization. Then add a method to your RPC interface:

Dummy dummy(Dummy d);

The implementation is just this:

Dummy dummy(Dummy d) { return d; }

And the async interface will have this:

void dummy(Dummy d, AsyncCallback< Dummy> callback);

The GWT compiler will pick this up, and because the Dummy class references those types, it will include them in the white list.

Example Dummy class:

public class Dummy implements IsSerializable {
    private java.sql.Date d;
}