GWT: RPC Failure (StatusCodeException) - gwt

Question

in my project an RPC interface was implemented to communicate between GWT and a server as described here:
http://code.google.com/webtoolkit/doc/1.6/DevGuideServerCommunication.html
All the existing methods can be invoked fine, but lately i introduced a new method which when calling it results in an RPC failure:
com.google.gwt.user.client.rpc.StatusCodeException: The call failed on the server; see server log for details
at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:192)
at com.google.gwt.http.client.Request.fireOnResponseReceivedImpl(Request.java:254)
at com.google.gwt.http.client.Request.fireOnResponseReceivedAndCatch(Request.java:226)
at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:217)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:592)
at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
at com.google.gwt.dev.shell.moz.MethodDispatch.invoke(MethodDispatch.java:80)
at org.eclipse.swt.internal.gtk.OS._g_main_context_iteration(Native Method)
at org.eclipse.swt.internal.gtk.OS.g_main_context_iteration(OS.java:1428)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2840)
at com.google.gwt.dev.GWTShell.pumpEventLoop(GWTShell.java:720)
at com.google.gwt.dev.GWTShell.run(GWTShell.java:593)
at com.google.gwt.dev.GWTShell.main(GWTShell.java:357)
(This excecption stacktrace is shown when running in hosted mode).
Here's the changes I made:
I extended my service interface with the new method:
#RemoteServiceRelativePath("myservice")
public interface MyService extends RemoteService {
// ...
Boolean isSomethingValid(String paramToCheck);
}
I implemented my method:
public class PMyServiceImpl extends GWTSpringController implements MyService {
// ...
public Boolean isSomethingValid(String paramToCheck) {
// do something ...
}
}
I added the method definition to the asynchronous interface:
public interface MyServiceAsync {
// ...
void isSomethingValid(String paramToCheck, AsyncCallback callback);
}
That's it. Am I missing anything? Any hints why the RPC failure occurs? In my server log, I can see the following exception:
[7/26/11 11:48:16:618 CEST] 0000004a WebApp A SRVE0181I: [myapplication.war] [/istoolset] [Servlet.LOG]: Exception while dispatching incoming RPC call: com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract java.lang.Boolean com.ubs.istoolset.front.fet.gwt.businessmodel.client.service.MyService.isSomethingValid(java.lang.String)' threw an unexpected exception: java.lang.NullPointerException
at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:360)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:546)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:164)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.doPost(RemoteServiceServlet.java:86)
at com.ubs.istoolset.gwt.framework.rpc.GWTSpringController.handleRequest(GWTSpringController.java:48)
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:859)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:793)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:476)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:441)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:763)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1146)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:593)
at com.ibm.ws.wswebcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:534)
at com.ibm.ws.webcontainer.servlet.CacheServletWrapper.handleRequest(CacheServletWrapper.java:90)
at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:764)
at com.ibm.ws.wswebcontainer.WebContainer.handleRequest(WebContainer.java:1478)
at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:133)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:450)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:508)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:296)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:270)
at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.sendToDiscriminators(NewConnectionInitialReadCallback.java:214)
at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.complete(NewConnectionInitialReadCallback.java:113)
at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165)
at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217)
at com.ibm.io.async.AsyncChannelFuture$1.run(AsyncChannelFuture.java:205)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1497)
Caused by: java.lang.NullPointerException
at com.ubs.istoolset.front.fet.gwt.businessmodel.server.MyServiceImpl.isSomethingValid(MyServiceImpl.java:1906)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:79)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:618)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:527)
... 27 more
Any help is very appreciated, thanks!

Answer 1

I'm not familiar with the com.ubs namespace (is that your code?), but this NullPointerException in your stack trace (server side) is a problem:
Caused by: java.lang.NullPointerException
at com.ubs.istoolset.front.fet.gwt.businessmodel.server.MyServiceImpl.isSomethingValid(MyServiceImpl.java:1906)
what is going on there?