Its not so much about performance its more about the resulting code size of your final JS. If you use List in your interface that extends RemoteService (or any DTO that is used with GWT-RPC) the GWT-RPC code generator can not know which concrete types the server side may return. Thus it has to generate de/serializer for all possible List implementations. This bloats your final JS code.
The interface that extends RemoteService should have the concrete type. Not sure about the Async interface, but I think GWT forces you that both interfaces match each other. I guess you can easily test it yourself with a small GWT project. If you know that you use all possible implementations of an interface, then its totally fine to use the interface instead of a concrete type. E.g. in a command pattern you can have an execute(Command) method because at some point in your app flow you have used all possible commands anyways. -- J. -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To unsubscribe from this group and stop receiving emails from it, send an email to google-web-toolkit+unsubscr...@googlegroups.com. To post to this group, send email to google-web-toolkit@googlegroups.com. Visit this group at http://groups.google.com/group/google-web-toolkit. For more options, visit https://groups.google.com/groups/opt_out.
