Erreur RPC après la mise à niveau de GWT 2.3

Question

Après la mise à niveau vers GWT 2.3, certains de mes services RPC ne fonctionnent plus et échouent avec "la réponse ne pouvait pas être désérialisée". Il semble arriver aux services qui renvoient des objets qui utilisent des objets de date qui sont annotés avec @temporal (temporaltype.timestamp). J'utilise Gilead 1.3.2 et Hibernate 3.6 et je n'ai eu aucun problème avec GWT 2.2. Une idée de ce qui pourrait se passer, ou comment commencer le débogage?

Voici la trace de pile:

com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException: The response could not be deserialized
  at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:221)
  at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java: 287)
  at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
  at sun.reflect.GeneratedMethodAccessor33.invoke(Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImp l.java:25)
  at java.lang.reflect.Method.invoke(Method.java:597) 
  at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
  at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
  at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:167)
  at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:326)
  at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:207)
  at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:132)
  at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
  at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
  at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
  at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
  at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
  at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:214)
  at sun.reflect.GeneratedMethodAccessor27.invoke(Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  at java.lang.reflect.Method.invoke(Method.java:597)
  at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
  at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
  at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:167)
  at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281)
  at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531)
  at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352)
  at java.lang.Thread.run(Thread.java:680)
Caused by: com.google.gwt.user.client.rpc.SerializationException: java.sql.Timestamp/1769758459
Caused by: com.google.gwt.user.client.rpc.SerializationException: java.sql.Timestamp/1769758459
  at com.google.gwt.user.client.rpc.impl.SerializerBase.getTypeHandler(SerializerBase.java:153)
  at com.google.gwt.user.client.rpc.impl.SerializerBase.instantiate(SerializerBase.java:114)
  at com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader.deserialize(ClientSerializationStreamReader.java:111)
  at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader.readObject(AbstractSerializationStreamReader.java:119)
  at com.lensoo.shared.entity.Course_FieldSerializer.deserialize(Course_FieldSerializer.java:320)
  at com.lensoo.shared.entity.Course_FieldSerializer.deserial(Course_FieldSerializer.java:405)
  at com.google.gwt.user.client.rpc.impl.SerializerBase.deserialize(SerializerBase.java:95)
  at com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader.deserialize(ClientSerializationStreamReader.java:113)
  at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader.readObject(AbstractSerializationStreamReader.java:119)
  at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter$ResponseReader$8.read(RequestCallbackAdapter.java:106) 
  at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:214)
  ... 26 more 
  ... 26 more