Unable to deploy on GAE with Objectify 4.0rc1 NoSuchMethod on class Key.getAppIdNamespace

[visheshd via StackOverflow]

I am using Motomapia as a reference app engine app to use Objectify 4.0rc1.

After deploying the app and sending a request that saves a user by calling

ofy().save().entity(newUser).now();

Where it fails with the following exception

com.sun.jersey.spi.container.ContainerResponse mapMappableContainerException: The exception contained within MappableContainerException could not be mapped to a response, re-throwing to the HTTP container
java.lang.NoSuchMethodError: com.google.appengine.api.datastore.Key.getAppIdNamespace()Lcom/google/appengine/api/datastore/AppIdNamespace;
at com.google.appengine.api.datastore.KeyTranslator.convertToPb(KeyTranslator.java:49)
at com.google.appengine.api.datastore.EntityTranslator.convertToPb(EntityTranslator.java:50)
at com.google.appengine.api.datastore.AsyncDatastoreServiceImpl.doBatchPutBySize(AsyncDatastoreServiceImpl.java:532)
at com.google.appengine.api.datastore.AsyncDatastoreServiceImpl.doIndexedEntityBatchPutBySize(AsyncDatastoreServiceImpl.java:629)
at com.google.appengine.api.datastore.AsyncDatastoreServiceImpl.put(AsyncDatastoreServiceImpl.java:464)
at com.googlecode.objectify.cache.CachingAsyncDatastoreService.put(CachingAsyncDatastoreService.java:415)
at com.googlecode.objectify.impl.WriteEngine.save(WriteEngine.java:79)
at com.googlecode.objectify.impl.SaverImpl.entities(SaverImpl.java:60)
at com.googlecode.objectify.impl.SaverImpl.entity(SaverImpl.java:35)
at com.xxxx.controller.user.RegisterController.index(RegisterController.java:44)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:45)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1511)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1442)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1391)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1381)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at com.google.inject.servlet.ServletDefinition.doService(ServletDefinition.java:263)
at com.google.inject.servlet.ServletDefinition.service(ServletDefinition.java:178)
at com.google.inject.servlet.ManagedServletPipeline.service(ManagedServletPipeline.java:91)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:62)

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http://stackoverflow.com/questions/16998547/unable-to-deploy-on-gae-with-objectify-4-0rc1-nosuchmethod-on-class-key-getappid