NoSuchMethod exception thrown in GWT

Question

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?

Answer 1

In your DocumentServiceImpl class, adding the following log:

System.out.println(Thread.currentThread().getContextClassLoader().getResource("org/externalmodel/MyReallyValidClass.class");

should tell you where this jar is being picked up.