I have not solved this problem either and has not time to closely look at how SeamResourceServlet is integrated with GWT. Following are what i have tried and still Not able to solve a simple RPC call yet.
1) Starting from Seam-2.0.1CR1, i rearrange jpa booking example to make sure that it works from the source. Similarly, i re-custom GWT Kitchen sink to make it work for my purpose.
2) To hook GWT and Seam together, i follow the Seam-GWT chapter in the ref doc. The ant task does not wotk, so i write my simple ant task to transfer GWT generated client system to seam webapp that the index page is pointed to. The task also transfers required client objects such as the service, ValidationUtility and serializable transfer object to the client module under Seam to be recompiled under jdk6 (instead of jdk4 for the client system) with gwt-servlet-1.4 taken from GWT package.
3) The SeamResourceServlet is mapped in web.xml to /hub/resource/* and the endpoint URL in GWT widget to invoke the async service is mapped to /hub/resource/gwt. Different mappings are tried with no better result.
4) Putting the compiled seam application to tomcat 6, GWT client-side system is up appropriately. Using the suggested ValidationUtility in both client and server side, i see the ValidationUtility work on the client side. But once it passes the validation to be send to the server, the seam server implementation does not response and the communication between client-server always fail. The problem may come from the connection point between GWT generated implementation of XxxServiceAsync and seam component implementation of XxxServiceImpl.
I do like to have this simple integration ironed out before we can do any things more interesting. Hope someone can help.
I just tested the GWT example in latest CVS (after doing a clean build) and it works fine. Your URL (http://localhost:8080//seam/resource/gwt) seems to be missing the context path, perhaps that is your problem?
Have you tried with just tomcat6 (jdk1.6) and GWT-1.4 (jdk1.4)? As explained in my posting, i use Seam-2.0.1-CR1, mapped SeamResourceServlet to /hub/resource/* and the endpoint URL in GWT widget to /hub/resource/gwt. I make sure that it works as stand-alone Seam Jpa example and GWT KitchenSink. The RPC integration did not work for me :-(. Is it worth to try the latest version from the source?