I'm starting to get my feet wet in the latest Google Web Toolkit using the Eclipse plugin on OS X 10.5.8. So far I've been able to get the client up and running, which is great. The server, though, is a different matter. I'm trying to link to a .jar file that has some classes I want to use in a server ServiceImpl class, but it seems to have glommed onto a previous iteration of the .jar - I've added a method, rebuilt the jar, removed the jar from the libraries tab on the GWT project's build path (as well as on the exports) and reincluded the jar. No luck - I'm still getting: [WARN] Exception while dispatching incoming RPC call com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract org.gwtapplication.client.LWDocument org.gwtapplication.client.DocumentService.getDocument()' threw an unexpected exception: java.lang.NoSuchMethodError: org.externalmodel.MyReallyValidClass.toSomething()Ljava/lang/String; at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:378) at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:581) ... Caused by: java.lang.NoSuchMethodError: org.externalmodel.MyReallyValidClass.toSomething()Ljava/lang/String; at org.application.server.DocumentServiceImpl.getDocument(DocumentServiceImpl.java:45) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) Eclipse's code sense has no problems resolving the MyReallyValidClass.toSomething() call, and there are no errors with other calls into the externalmodel classes. Any clue where I should be looking?